NOAA Technical Memorandum NMFS-SEFSC- 463

Acoustic and Visual Survey of Cetaceans in the Waters of Puerto Rico and the Virgin Islands: February – March 2001

Steven L. Swartz, Anthony Martinez, Jack Stamates, Carolyn Burks, and Antonio A. Mignucci-Giannoni 70° 69 ° 68° 67° 6 6° 65° 64° 63°

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U.S. Department of Commerce National Oceanic and Atmospheric Administration NOAA Fisheries Southeast Fisheries Science Center 75 Virginia Beach Drive Miami, Florida 33149

January 2002 Acoustic and Visual Survey of Cetaceans in the Waters of Puerto Rico and the Virgin Islands: February – March 2001

Steven L. Swartz and Anthony Martinez Southeast Fisheries Science Center, NOAA Fisheries, Miami, Florida, USA

Jack Stamates Atlantic Meteorological and Oceanographic Laboratory, NOAA, OAR, Miami, Florida, USA

Carolyn Burks Southeast Fisheries Science Center, NOAA Fisheries, Pascagoula, Mississippi, USA

Antonio A. Mignucci-Giannoni Caribbean Marine Mammal Laboratory Universidad Metropolitana, San Juan, Puerto Rico

U.S. DEPARTMENT OF COMMERCE Donald L. Evans, Secretary

National Oceanic and Atmospheric Administration Scott B. Gudes, Under Secretary of Oceans and Atmosphere

NOAA Fisheries William T. Hogarth, Assistant Administrator for Fisheries

January 2002

This Technical Memorandum series is used for documentation and timely communication of preliminary results, interim reports, or similar special-purpose information. Although the memoranda are not subject to complete formal review, editoral control, or detailed editing, they are expected to reflect sound professional work. NOTICE

NOAA Fisheries does not approve, recommend or endorse any proprietary product of material mentioned in this publication. No reference shall be made to NOAA Fisheries or to this publication furnished by NOAA Fisheries, in any advertising or sales promotion which would imply the NOAA Fisheries approves, recommends, or endorses any proprietary product or proprietary material mentioned herein or which has as its purpose any intent to cause directly or indirectly the advertised product to be used or purchased because of this NOAA Fisheries publication.

This report should be cited as follows:

Swartz, S.L., A. Martinez, J. Stamates, C. Burks, and A.A. Mignucci-Giannoni. 2001. Acoustic and visual survey of cetaceans in the waters of Puerto Rico and the Virgin Islands: February-March 2001. NOAA Technical Memorandum NMFS-SEFSC- 463, 62 p.

This report has an internal document number PRD-01/02-01.

Copies may be obtained by writing:

Director, Protected Resources Branch or National Technical Information Center Southeast Fisheries Science Center 5825 Port Royal Road NOAA Fisheries Springfield, VA 22161 75 Virginia Beach Drive (703) 605-6000, (800) 553-6847 Miami, FL 33149 Http://www.ntis.gov/numbers.htm

Summary

A visual and acoustic survey for humpback whales and other cetaceans was conducted from 12 February to 8 March 2001 in the waters to the east of the Bahamas and around Puerto Rico and the Virgin Islands. The survey utilized passive acoustic techniques (directional sonobuoys and a towed hydrophone array) to augment traditional visual surveys for cetaceans. Several previously unreported areas of humpback whale aggregation were discovered around Puerto Rico, off the east coast of the Dominican Republic, and east and southeast of the Virgin Islands. Samples of humpback whale song were obtained for stock analysis. Additional recordings from sperm whales, other cetaceans, and Atlantic thump trains were obtained. Lists of the species encountered and their distributions, and sounds recorded are presented in 4 tables and 24 figures that accompany the text.

-i- CONTENTS Page

INTRODUCTION...... 1 BACKGROUND...... 1 METHODS...... 3 Survey Track and Timing...... 3 Visual Survey...... 3 Acoustic Survey...... 4 Sonobuoys...... 5 Towed Hydrophone Array...... 6 Autonomous Acoustic Recorders...... 6

RESULTS

Visual Surveys...... 7 Estimation of Abundance...... 7 Acoustic Surveys...... 7 Humpback Whale Detections...... 8 Sperm Whale Detections...... 10 Atlantic Thumptrains...... 10 Anthropogenic Noise ...... 10 Autonomous Acoustic Recorders...... 11

DISCUSSION

Visual and Acoustic Detections...... 11 Humpback Whale Distribution...... 12 Atlantic Thumptrains...... 13 Anthropogenic Noise ...... 14 Autonomous Acoustic Recorders...... 14 Future Surveys...... 15

ACKNOWLEDGMENTS...... 17

LITERATURE CITED...... 18

TABLES AND FIGURES...... 22

-ii- Acoustic and Visual Survey of Cetaceans in the Waters of Puerto Rico and the Virgin Islands: February – March 2001

INTRODUCTION

Marine mammals are protected in U.S. waters (State, Territorial, and U.S. Exclusive Economic Zone) under the Maine Mammal Protection Act (MMPA, 16 U.S.C. 1361 et seq.), and the Endangered Species Act (ESA, 16 U.S.C. 1531 et seq.). The 1994 Amendments to the MMPA require NOAA Fisheries (NMFS) to monitor trends in abundance and distribution of all marine mammals in U.S. waters. Similarly, the ESA requires monitoring of endangered and threatened marine mammal populations in U.S. waters until such time as their populations recover and are removed from the list of endangered and threatened wildlife. The NMFS’ Southeast Fisheries Science Center (SEFSC) developed a scientifically based survey program to provide statistically reliable information on the status of these protected living marine resources on a long-term basis to implement the status of stocks requirement of the 1994 amendments to the MMPA. This information is needed to detect and identify significant changes in the seasonal abundance and distribution of marine mammals that may be indicative of human related disturbance and natural population cycles.

This report presents the findings of a vessel based visual and passive acoustic survey for cetaceans conducted from February 12, 2001 to March 8, 2001 in the waters of the northeastern Caribbean including Puerto Rico and the Virgin Islands.

BACKGROUND

At least 13 species of odontocete and four species of mysticete cetaceans are found in the waters of the Puerto Rican bank, which includes Puerto Rico and the U.S. and British Virgin Islands (Erdman, et al. 1973, Mignucci-Giannoni 1998). The seasonal abundance and distribution for most of these species in the northeastern Caribbean are poorly known (Roden and Mullin 2000, Mignucci-Giannoni 1989, Mignucci-Giannoni et al. 1999).

One exception is the endangered North Atlantic humpback whale (Megaptera novaeangliae) which migrates in winter to breeding grounds in and around the Greater and Lesser Antilles (Clapham and Mead 1999, Swartz et al. 2001). The North Atlantic humpback population as recovered from commercial exploitation to an estimated 10,500 animals (Smith et al. 1999), however it remains listed as endangered under the ESA. The largest known and best studied winter concentrations of humpback whales presently occur in the waters of Silver and Navidad Banks off the northeastern coast of Dominican Republic and northern part of the Antillean chain. There, hundreds of humpbacks gather from January to March each year to breed and give birth to their calves (Balcomb and Nichols 1982,

1 Whitehead and Moore 1982, Winn et al. 1975, Whitehead 1982, Mattila et al. 1989). Lower densities of humpbacks have been reported in adjacent areas immediately to the east, including the Mona Passage (Puerto Rico), and the Virgin Bank and Anguilla Bank (Mattila and Clapham 1989).

The endangered sperm whale (Physeter macrocephalus) is the second large cetacean most frequently seen in the northeastern Caribbean (Roden and Mullin 2000). Like humpback whales, sperm whales are distributed in all of the world’s oceans. For management purposes the International Whaling Commission defines four stocks: the North Pacific, the North Atlantic, the Northern Indian Ocean, and Southern Hemisphere, however, there is no clear picture of the worldwide stock structure of sperm whales. In general, females and immature sperm whales appear to be restricted in range, whereas males are found over wider ranges and appear to make occasional movements across and between ocean basins (Dufault et al. 1999). Females and juveniles form pods that are restricted mainly to tropical and temperate latitudes (between 50/N and 50/S) while the solitary adult males can be found at higher latitudes (between 75/N and 75/S) (Reeves and Whitehead, 1997). In the western North Atlantic they range from Greenland to the Gulf of Mexico and the Caribbean.

Some 20 living species of beaked whales (Ziphiidae spp.) are distributed worldwide, rank second only to the delphinids in diversity, and remain the most poorly-known family (Rice 1998). Sightings and strandings of beaked whales (Ziphius cavirostris and Mesoplodon spp.) have been reported from many locations in the Caribbean, suggesting that these species may be fairly common (Mullin and Roden 2000, Mignucci-Giannoni 1998, Mignucci et al. 1999). Their distribution in the northern Caribbean appears to be limited to tropical and warm-temperate waters. They are generally found off the continental and insular shelves over deep water where they are believed to feed on cephalopod prey.

Because they spend large amounts of time at depth and use low-to-high frequency sound for communication and echolocation, humpback, sperm, beaked, and other whales and dolphins are likely to be vulnerable to any negative effects of anthropogenic sound in the ocean (Richardson et al. 1995). While many whales and dolphins are abundant on a world-wide scale, their potential rate of reproduction is relatively low and many regional populations are believed to be small resident stocks. The potential cumulative effects from long-term exposure to noise resulting from activities associated with human industrial activities are of concern, and could include changes in whale and dolphin seasonal abundance and distribution. Reliable baseline information on the seasonal abundance and distribution of whales and dolphins is required to detect and evaluate any demographic changes that could be the result of exposure to noise or other factors in the ocean habitat.

To investigate the current abundance and distribution of cetaceans wintering in the Lesser and Greater Antilles a combined passive acoustic and visual vessel survey was conducted by SEFSC during February and March 2001. The specific objectives of that survey were to:

1. Conduct visual line-transect and passive acoustic surveys to determine the winter distribution and abundance of cetaceans in the waters around Puerto Rico and the Virgin Islands.

2 2. Collect recordings of vocalizations and other sounds from all cetacean species encountered for reference and comparison among regions.

3. Collect associated environmental data (i.e., sea surface temperature and temperature at depth, wind profiles, and ambient noise measurements) at designated sites within the study area.

4. Deploy and retrieve two acoustic bottom recorders to test the feasibility of utilizing such devices for long-term acoustic monitoring at designated sites.

METHODS

The combined passive acoustic and visual survey was conducted on the NOAA ship Gordon Gunter, a 75 m long oceanographic research vessel designed to support surveys for cetaceans in pelagic and coastal waters 11 m or deeper (Fig. 1). The vessel is powered by diesel-electric engines, which are acoustically quiet and produce minimal low-frequency background noise during survey operations.

Survey Track and Timing

The survey consisted of two legs comprising a total of 6,945 km of track line. Total visual survey effort was 3,518 km, and total acoustic monitoring effort was 6,044 km. The first survey leg began on 12 February 2001 and concluded on 19 February 2001. This leg began south of Abaco Island in the Bahamas chain and continued southward along the eastern side of the Bahamas past Caicos, Mouchoir, Silver and Navidad Banks. This leg then continued southward through the Mona Channel, eastward along the southern side of Puerto Rico to Vieques Island, then continuing northward through the Virgin Passage and surveyed the insular shelf waters to the northeast of Puerto Rico, and concluded at the Port of San Juan (Fig.2). The second survey leg began in San Juan on 21 February 2001 and included the insular and offshore waters to the north of Puerto Rico including the southern portion of the Puerto Rico Trench (21-23 February 2001), the insular shelf and offshore waters south of Puerto Rico (24-25 February 2001), the Mona Channel including the coastal waters of the Dominican Republic, the insular shelf waters along the northwestern side of Puerto Rico (26 February to 6 March 2001), and insular shelf waters around the Virgin Islands and St. Croix (7-8 March 2001).

Visual Survey

This survey was designed to provide a general picture of the relative abundance and distribution of cetaceans in specific locations. Thus, survey track lines were developed to circumnavigate the coastlines of the islands and offshore banks surveyed, except for the insular waters around Puerto Rico. The survey track line around Puerto Rico was designed to allow estimation of the most abundant marine mammal species; however, the survey plan had to be modified to accommodate ongoing military operations in the area. As a result, survey coverage of the insular waters around Puerto Rico and the

3 estimation of marine mammal abundance was limited.

Visual survey operations for cetaceans were conducted following standard NMFS survey protocols (Barlow 1995). On-effort survey mode switched to off-effort mode when either visual conditions deteriorated (due to sea state > Beaufort 5), or if the ship left the trackline to locate cetaceans for group size estimation, or to record humpback song or other cetacean vocalizations. Visual observations were normally conducted from 0630 hrs to sunset (approximately 1930 hrs) each day. Two teams of three experienced observers operated rotating 2-hr shifts during daylight hours, weather permitting (i.e., no rain, Beaufort sea state < 5, winds below approximately 22 kts.). Observers rotated through each of three observer positions every 30-min. to reduce fatigue. Observations were made from the flying bridge, located approximately 14 m above the sea surface. A port and a starboard observer each searched for cetaceans using 25X “big eye” binoculars within a 900 quadrant from the bow to the beam on each side of the ship (Fig. 3) . A third observer recorded data and maintained a search of the area near the ship using unaided eye and/or 7X hand-held binoculars.

When cetaceans were sighted, the ship broke from its track and approached the cetaceans to confirm species and to estimate group size. Sighting data were recorded on a laptop computer using a data acquisition and logging software program that interfaced with the ship’s global positioning system (GPS). Cetacean sighting data included species, group-size, presence of calves, bearing from the bow, linear distance from the ship when detected, and behavioral observations. Each night, observers filled out sighting forms, and these were checked for errors and reconciled with the day’s computerized data log. Environmental data were recorded every half-hour with the rotation of observer positions, when conditions changed during a shift, and at the time of each sighing. Environmental data included sea state, surface temperature, water depth, weather, visibility, wind direction and speed, and sun glare in the observer’s field of view. A continuous record of the ship’s position, sea surface temperature (SST) and water depth was collected via the ship’s onboard Scientific Sensor Collection System (SSCS).

Acoustic Survey

Many cetaceans produce sounds that are detectable at substantial distances, and thus pasive acoustic methods are useful for determining presence and distribution of cetaceans, especially in conditions where visual survey methods have limited effectiveness (Noad and Cato 2001). The survey platform, the NOAA ship Gordon Gunter, is well suited for both visual and acoustic surveys. It is a former U.S. Navy vessel engineered to support passive acoustic operations. The ship is powered by deisel-electric engines which are acoustically quiet relative to power plants in other vessels, and produced minimal low-frequency background noise during survey operations. Monitoring to detect humpback whale song and other cetacean sounds was conducted throughout the primary survey area and opportunistically in other areas with the use of directional sonobuoys and a towed hydrophone array.

Sonobuoys: The AN-SSQ-53D directional (DIFAR) sonobuoy were used to detect and obtain directional in formation from calling whales. These sonobuoys contain a compass in the sensor head

4 and transmit three types of continuous signal back to the ship on a VHF radio carrier in an analog multiplexed format (Fig. 4). These signals are acoustic sound pressure, east/west particle velocity and north/south particle velocity. The frequency range is from approximately 10 Hz to 4,000 Hz, which is well suited for large whale vocalizations that have their greatest sound energy concentrated below 1,000 Hz. These sonobuoys could be set to broadcast for up to 8-hrs. A second type of sonobuoy, the AN-SSQ-57-A, had a frequency range from approximately 50 Hz to 20,000 Hz and were also used to obtain non-directional sound recordings from other cetaceans, particular the odontocete species encountered that vocalize in higher frequency ranges. All these data contribute to location and species specific library of signature calls for cetaceans, which will allow species identification when visual data are not available.

The VHF radio signal from the sonobuoys was received by a pair of antennas mounted on the aft mast of the ship located at 26 m above waterline. Each antenna was tuned for optimal reception over a range of radio frequencies. Sonobuoy radio broadcast frequencies were chosen near the frequency band of one or the other antenna, depending on the level of radio interference present on a specific frequency band. Radio reception ranges from the sonobuoys averaged 11-13 N.M. which, when the ship was running at survey speed (approximately 10 kts), allowed each sonobuoy to be monitored for approximately one hour and ten minutes before the ship moved out of radio reception range. The signals from the radios were recorded at a 48 kHz sampling rate on two-channel DAT tape recorders for processing and for archival purposes, and were monitored in real time on PC computers running SpectraPlus1, a commercial signal-analysis software program.

The magnetic bearing (or azimuth to the signal source relative to the position of the sonobuoy) to calling animals was determined by selecting a segment of the humpback song from the sonobuoy signal using the signal-analysis software program’s spectrogram display computed on the computers using standard sound cards. This signal was then stored as a binary file, de-multiplexed using custom software designed by Greeneridge Scientific, and the three de-multiplexed signals were processed to yield a magnetic bearing to the sound source using another custom software program written for this project by M. McDonald. This software produces a plot showing signal intensity as a function of frequency and bearing angle from 00 to 3600 relative to the position of the sonobuoy (Fig. 5). The bearing accuracy to a sound source using these buoys had a standard deviation of two degrees. Magnetic bearing angles to calling animals from the sonobuoys were plotted as true bearings on navigational charts to determine the direction to the calling whale relative to the position of the ship. The vagaries of acoustic propagation in the ocean made it impossible to accurately estimate range to a calling whale by received signal amplitude alone. However, when the same singing whale or whales were detected on two or more sonobuoys with a sufficient baseline separation, it was possible to precisely locate the calling whales by crossing two or more bearings to determine the source.

1 The use of commercial trade names does not imply endorsement by the authors.

5 Towed Hydrophone Array: The Southeast Fisheries Science Center’s 5-element towed array is a 100- meter long Kevlar reinforced cable assembly with five high gain hydrophones, spaced at two-meter intervals along the cable (Fig. 6). Each element is a piezoelectric ceramic striped cylinder with the cable assembly and strength member passing through the center. Each sensor, along with its associated signal conditioning, filtering and line drive electronics, is contained within a hydrodynamically shaped tow body assembly. The frequency response is essentially flat at -127 dB from about 2 kHz to 15 kHz then climbs to a resonance peak at about 35 kHz with a level of -121 dB, then drops off at roughly -15 dB per octave after resonance. Below 1.5 kHz, the sensors roll off at roughly 6 dB per octave to help reduce low frequency tow and impulse noise. The first element is located approximately 17 meters behind the forward underwater connector. The aft end of the array is terminated with another underwater connector, which allows for testing of the array wiring and for attachment of an additional array or sensor package. This entire assembly is connected to an 800-meter tow cable made from the same cable as found in the array. This constitutes the wet end of the assembly and it is deployed from and rewound onto a hydraulically powered winch/drum with a diameter of 1.2 meters. A deck cable running into the acoustics laboratory completes the assembly and allows for the transfer of power to and signal from the array.

As with the sonobuoys, the signals from each of the five hydrophone elements in the array were recorded in the laboratory at a 48 kHz sampling rate on 8-track DAT tape recorders for processing and for archival purposes. The incoming hydrophone signals were monitored in real time on PC computers running a custom software program “Ishmael” developed by D. Mellinger. This program allowed real-time signal monitoring and calculations of magnetic bearings to the sources of whale calls relative to the orientation of the ship.

Each evening following the termination of the visual surveys, the hydrophone array was deployed and towed at approximately 4 kts to minimize self noise and turbulance for optimum recording of ambient and biological sounds. A number of times during the survey DIFAR sonobuoys could not be used to record sounds near the shores of Puerto Rico due to radio and other electronic interference emanating from the island. In these instances, the vessel’s speed was reduced to approximately 7 kts from 10 kts for visual surveys, and the hydrophone array was used as a substitute for the sonobuoy to collect data on whale calls and ambient noise during visual surveys. While the reduction in speed was a compromise for the visual survey that is normally conducted at 10 kts, it provided a reasonable reduction in flow noise and turbulence from the array to allow for detection and recording of biological sounds from cetaceans.

Autonomous Acoustic Recorders: The Bioacoustics Research Program (BRP) at the Cornell University Laboratory of Ornithology provided two autonomous acoustic recorders (Pop-Ups) to monitor for whale sounds and ambient noise in the survey area. Each pop-up consists of a 17" Benthos glass sphere that contains batteries, communications electronics, and data collection electronics (DSP system with 25GB hard drive) (Figs. 7 and 8). A continuous sampling schedule was programmed for each recorder through a serial interface and PC software. Sampling rate range was set from 100 - 8,000 Hz

6 to allow detection of low frequency whale calls as well as higher frequency dolphin and small toothed whales.

RESULTS

Visual Surveys

A total of 142 cetacean groups representing 11 species of cetaceans were sighted during during both legs 1 and 2 of the survey, with the highest number of groups sighted per day being 38 (Tables 1 and 2). Sightings included: humpback whales (n=72) (Fig. 9), sperm whales (Physeter macrocephalus, n=6), beaked whales, (Ziphius cavirostris., n=3, and Mesoplodon spp., n=3), false killer whales (Pseudorca crassidens, n=1), pilot whales (Globicephala cf. macrorhynchus., n=8), rough-toothed dolphin (Steno bredanensis, n=1), bottlenose dolphin (Tursiops truncatus, n=2), pantropical spotted dolphin (Stenella attenuata (n=3), Atlantic spotted dolphin (Stenella frontalis, n=10), spinner dolphin (Stenella longirostris, n=2), unidentified dolphin (n=11), unidentified small whale (n=3), and unidentified large whale (n=13) (Figs. 10 and 11).

Estimation of Abundance: As noted in the methods section, the original survey track around Puerto Rico was designed to allow for the estimation of abundance of humpback and other whale species, however, the trackline and the sequence that each portion of the trackline were executed had to be modified to accommodate naval exercises that were ongoing in the area. As a result, the survey coverage around Puerto Rico and the Virgin Islands did not completely cover the entire insular shelf, and the sightings of most marine mammal species were too few to allow meaningful statistical analyses. There were, however, sufficient visual sightings of humpback whales within the insular shelf waters (n= 31 groups) to allow the calculation of a preliminary abundance estimate of 532 (CV 0.36, 95% CI 260-1,088) humpback whales on the Puerto Rico Bank during the February-March time frame. This estimate is likely negatively biased, as the findings of the 2000 acoustic and visual survey for humpback whales in the Eastern Caribbean (Noad and Douglas 2001, Swartz et al. 2001) suggested that acoustic detections outnumbered visual detections by a factor of as much as 8:1.

Acoustic Surveys

A total of 135 sonobuoys were deployed during the survey along approximately 6, 044 km of trackline (Fig. 12). Approximately 270 hours of 2-track DAT tape recordings were obtained from the sonobuoys and approximately 40 hours of 8-track DAT tape recordings of ambient sounds and whale calls were obtained during hydrophone array tows. While analysis of the hydrophone array tapes is ongoing, cetacean sounds recorded from the array included humpback whales, sperm whales, pilot whales, false killer whales, and a variety of dolphin calls (Table 3).

Humpback Whale Acoustic Detections: The northern most detection of a singing humpback whale was

7 obtained from a sonobuoy deployed east of Samana Cay in the Bahamas on February 14, 2001 (Fig. 13). The signals detected from the sonobuoy suggested that the calling whale was located a few kilometers to the north of Samana Cay. As the survey proceeded south, additional calling humpbacks were detected in increasing numbers off the east and southern end of Mayaguana Island, to the east of the Turks and Caicos, and east of Mouchoir Bank. These initial acoustic detections of humpback whales were not accompanied by visual detections due to strong winds and high sea states that limited visibility. The number of singing whales detected acoustically increased from one or a few individuals to choruses of many individual singers as the survey approached the well-known humpback aggregation sites of Silver and Navidad Banks. The first visual detections of humpback whales occurred on 15-16 February 2001 off the eastern sides of Silver and Navidad Banks along with continuous acoustic detections of many singers. The number of singing whales was so great in these locations that it was not possible to localize on the direction of an individual singer; rather, bearings to the general direction of the “chorus” of singing whales were obtained from the sonobuoy signals. Notably, a few sonobuoy bearings obtained off the eastern side of the Turks and Caicos and off Silver Bank suggested that some calling whales were located offshore to the northeast over very deep water (> 5,000 m). Similarly, during the last portion of the survey on 11-12 March 2001 choruses of singing whales were detected along the southern sides of Navidad, Silver, and Mouchoir Banks. In addition, sonobuoy detections indicated that additional whales were located along the northern shore of the Dominican Republic and Haiti. The last acoustic detection of singing humpbacks were from whales located along the southwestern shore of Great Inagua Island, Bahamas on 12 March 2001.

Surveys over the deep water of the Puerto Rican Trench northeast of Puerto Rico detected calls from singing humpback whales presumable located to the northwest in the direction of Navidad Bank, and also from whales located to the northeast and east over deep water (> 6,000 m) and far from any banks or islands (Fig. 14). The presence of humpback whales in this deep water was confirmed by visual sightings on 22-23 February 2001, along with sightings of sperm and pilot whales. Additional acoustic bearings suggested that singers were located to the southeast toward the islands of Anguilla, St. Martin, and St. Barthélemy, and from whales located on the northern side of the insular shelf of the Virgin Islands. Multiple acoustic and visual detections of humpback whales were obtained along the shelf waters of the Virgin Bank to the northwest and north of the Virgin Islands on 17-18 February and on 7 March 2001. Groups of many chorusing humpback whales were detected east and southeast of Anegada Island on 7-8 March 2001. Here the numbers of individually singing whales created a chorus of songs similar in amplitude to that detected off of Silver and Navidad Banks, suggesting high densities of whales were located on the coastal banks to the east and southeast of Anegada Island.

The survey conducted on 8 March 2001 traversed the channel between the Virgin Islands and St. Croix (Fig. 15). Humpback whales were detected visually and acoustically on Barracuda Bank southeast of the British Virgin Islands and off the east end of St. Croix. Surface active groups of presumably mating humpbacks along with lone individual whales were seen in these areas. Acoustic detections suggested that additional singing whales were located to the southeast in the direction of Saba Bank, St. Kitts and Nevis. Surveys of the insular shelf waters southeast of Puerto Rico resulted in

8 no visual sightings of humpbacks, but singing humpback whales were acoustically detected in all directions except to the north in the direction of Vieques Island and the Puerto Rican mainland. Similarly, surveys of the offshore waters south of Puerto Rico on 26-27 February 2001 resulted in no visual sightings of humpback whales. Acoustic detections of humpback whales from sonobuoys placed in this area resulted in bearings to singing whales located to the northeast toward Saba Bank and St. Croix, and to the northwest in the direction of Cabo Rojo (southwest Puerto Rico) and the Mona Channel. A few bearings obtained in this deep-water area suggested that some distant callers were located to the south of Puerto Rico at some yet to be determined location.

Surveys off the southwestern coast of Puerto Rico on 1-2 March 2001 resulted in no visual sightings of humpback whales, however, multiple acoustic detections suggested that singers were located to the north and northeast in the region of Cabo Rojo and Mona Island in the southern end of Mona Channel (Fig. 16). It should be noted that all the acoustic bearings to singing whales were to the north, and there was no indication that additional singing humpback whales were located to the south of the southernmost sonobuoys. Humpback whales were sighted to the west of Cabo Rojo along the edge of the insular shelf, and to the west around the northern shores of Mona Island. The frequency and numbers of calling humpback whales in the Cabo Rojo area and along the northern shore of Mona Island were comparable to that detected off Silver and Navidad Banks to the north suggesting that dense aggregations of humpback whales occupied these locations. In contrast, the survey of the area to the west of Mona Island and along the southeastern shore of the Dominican Republic off Isla Saona detected no humpback whales is this region. All the bearings from sonobuoys deployed in this area suggested that singing whales were those previously detected to the east and northeast in the Mona Channel.

The survey from the southeast corner of the Dominican Republic north to Cabo Engaño and Engañno Bank on 3 March 2001 revealed no sightings of humpback whales, but acoustic detections pointed to sources of whale songs to the east toward Mona Island and to the north at Engaño Bank. As the survey approached Engaño Bank, visual sightings of humpback whales increased along with acoustic detections (Fig. 17). The number of chorusing humpback whales detected on Engaño Bank were similar to that recorded on Silver and Navidad Banks to the north, suggesting that this area was a significant aggregation area for humpback whales. The survey crossed the northern Mona Channel toward Puerto Rico on March 4, 2001. Visual and acoustic detections indicated that concentrations of humpbacks were located on the insular shelf off the northwestern coast of Puerto Rico. As the survey moved to the northwest away from the Puerto Rican coast into deep offshore water, visual sightings of humpback whales declined. Acoustic detections in this area produced bearings to singing whales off toward Samaná Bay in the Dominican Republic to the west (a well documented humpback aggregation area), and to Navidad Bank to the northwest. Similarly, acoustic detections of singing humpbacks obtained off the northern coast of Puerto Rico pointed to whales located to the east in the vicinity of the Virgin Islands and to the west in the northern Mona Channel.

Sperm Whale Acoustic Detections: Classic “clicks” and “codas” from sperm whales were detected on

9 12 (9%) of the 135 sonobuoys deployed around Puerto Rico (Fig. 18). Most of these sperm whale detections were located to the southwest of Puerto Rico over relatively deep water and in the Mona Channel to the southwest of Mona Island.

Atlantic Thumptrain Detections: Atlantic "thumptrain" calls were the second most frequently detected biological sounds next to humpback whale calls. “Thumptrains” are believed to be attributed to minke whales (Balaenoptera acutorostrata) (Mellinger et al. 2001), although no minke whales were visually detected during this survey (Fig.19). Multiple thumptrains were detected on 79 (58%) of 135 sonobuoys. These thumptrains consist of a series of repetitive pulses approximately 1.0-1.5 seconds apart with a major center of energy between 200 HZ and 400 Hz that continue for 20 seconds to over one minute in length (Fig. 20). As the thumptrain proceeds, the rate of the individual pulses increases or speeds up to a crescendo and an abrupt termination of the signal. Thumptrains were frequently recorded in the presence of humpback whale calls.

Anthropogenic Noise: A total of 50 percussive “explosion-like” sounds were recorded on 7 sonobuoys (n=43) and during 6 hydrophone array tows (n=7)(Table 4). The first instance was recorded during array tow TA-01 on 22 February 2001 near the eastern edge of the outer northern naval operations range. Additional percussive sounds were subsequently recorded on sonobuoys and during array tows between 25 February and 1 March 2002 south of Puerto Rico. Magnetic bearings calculated from sonobuoy numbers SB-95, SB-96, SB-99, SB-100, and SB-102 suggested that the sources of these percussive sounds were centered within the southern inner naval operations range at Latitude 170 48.4 N Longitude 650 48.4 W approximately 91-163 km from the sonobuoys (Fig. 21). Additional sounds recorded on sonobuoy SB-108 on 1 March 2001 suggested that their source was the area to the south of Vieques Island approximately 252 km from the sonobuoy. We were not equipped to make quantitative measurements of recieved sound levels, however, we could compare relative sound level to prevailing ambient noise at the time these percussive sounds were recorded. A spectral power analysis of one of these percussive sounds recorded from the towed hydrophone array on 27 February 2001 (TA-06) indicates that between 100 Hz and 20 kHz the received sound level at the array averaged approximately 26.86 dB (re. 1 : Pa-m) above the ambient noise level in the area just prior to the occurrence of the percussive sound (Fig. 22). At that time the array was approximately 98 km from the center of the southern inner operations range.

Sound from commercial ships was frequently encountered all around Puerto Rico except off the southeast corner of the island. Shipping noise was characteristically broadband with major energy components between 20Hz to 600Hz or higher. A total of 22 (16%) of 135 sonobuoys detected noise from commercial ships (Fig. 23). Active sonar pings were also recorded on 6 occasions: once on a sonobuoy (SB-48) and 5 times during towed hyrdophone arrays (TA-08, TA-09, TA-12, TA-14, and TA-18).

10 Autonomous Acoustic Recorders

Two "pop-up" autonomous sea-floor recording devices provided by Cornell University were deployed in two locations off Puerto Rico to monitor for cetaceans and collect ambient sound data. Data from both units were downloaded, converted into AIF files and archived on several large disk drives. Converted files were scanned for humpback whales on an ad hoc basis. In both locations there was considerable vessel noise as well as occasional humpback singing.

The first recording device was placed in the northern Mona Channel, approximately 15 km southwest of Desecheo Island, on 16 February 2001 in approximately 300m depth (Fig.17). The second device was placed approximately 8 km south of Vieques Island on February 17, 2001 in approximately 538m depth (Fig. 15). The recorder deployed off Vieques Island was recovered on February 25, 2001 having recorded for 8.3 days, however, usable recordings were obtained for only approximately 47 hours (8 GB of data) beginning on February 23, 2001. Sperm whale clicks were recorded along with various instances of manmade sound during the period the unit operated. Most of the manmade sounds consisted of vessels moving past this area. Other sounds that are assumed to be manmade have yet to be identified. Unfortunately, the quality of recorded sound from this buoy was marginal and a more thorough analysis is required to determine the complete nature of the sounds recorded.

The recorder located off Desecheo Island was recovered on March 2, 2001 having recorded for 14 days. The quality of recorded sound from this device was much better than the device placed off Vieques Island. Sounds from several species of cetaceans were present on recordings, including humpback whales which account for most of the marine mammal sounds recorded. There are also various instances of delphinid whistles that have not been identified to a species. Vessels in transit account for the bulk of manmade sounds recorded, and are seen a peaks in the spectoral data in the low-noise band (10-100 Hz) and mid-noise band (100-300 Hz) recorded over several days (Fig. 7). There are humpback whale calls and other cetacean sounds embeded in these data along with a few instances of what appears to be active sonar pings.

DISCUSSION Visual and Acoustic Detections

The sightings of cetaceans obtained during this survey were typical for the region and consistent with published species accounts from previous surveys of the area (Erdman, et al. 1973, Mignucci-Giannoni 1998, Roden and Mullin 2000). While the eleven of the 13 species of cetaceans observed in this survey were representative of the odontocete and mysticete cetaceans found in the waters of the northeast Greater Antilles around Puerto Rico and the Virgin Islands, the encounter rates were lower than expected, and precluded statistically meaningful estimation of abundance.

The exception was the humpback whale. The provisional abundance estimate of 532 (CV 0.36, 95% CI 260-1,088) for humpback whales on the Puerto Rican-Virgin Island insular shelf is based on

11 sightings of 31 groups of whales, and is likely an underestimate of the number of humpbacks that utilized these areas as winter aggregation sites. The 8:1 ratio of acoustic detections to visual detections of humpback whales observed in the Eastern Caribbean (Swartz et al. 2001) suggests that visual methods alone greatly underestimate humpback whale density (Noad and Douglas 2001). Ongoing analyses of the findings from this survey include developing acoustic based estimates of relative density and abundance of singing and other age/sex classes of humpback whales that frequent the aggregating areas described in this study. The goal of these analyses is to develop a correction factor for this region that will allow a more precise estimation of humpback whale density and abundance during the February-March time frame. Future surveys will need to expand the coverage of this survey to adjacent areas within the Greater Antilles to confirm the absence and/or presence of humpback whale aggregations during the winter breeding seasons, and to provide a context in which to evaluate trends in humpback whales and other cetacean species around Puerto Rico and the Virgin Islands.

Humpback whales were the most frequently sighted cetacean, and they were the species most frequently detected acoustically. Clearly the use of passive acoustic methods to detected singing humpback whales contributed to a clearer and more complete determination of their winter distribution and relative density is specific areas in and around the Puerto Rican and Virgin Island insular shelf than would have been obtained by visual methods alone. Over time, the continued use of sonobuoys and towed hydrophone arrays will add new information on the signature vocalizations and calls of specific to all species of cetaceans. Ultimately these species specific sounds will allow the identification, presence or absence, and distribution of these species on a seasonal basis from acoustic information alone. In the long-term, a network of bottom mounted acoustic sensors could provide real-time or near-real time monitoring of the acoustic environment around Puerto Rico and adjacent waters on a seasonal basis. Periodic vessel based surveys employing both visual and passive acoustic survey methods could be used to validate such data gathered over the long-term by these acoustic devices.

Humpback whale distribution: The findings of this survey reaffirmed the continued use of previously identified winter aggregation areas of humpback whales including Silver and Navidad Banks off the northeast coast of the Dominican Republic (Whitehead and Moore 1982, Mattila et al. 1989), Samaná Bay (Mattila et al. 1989), Rincon and Borinquen bank (Mattila 1984, Mignucci-giannoni 1998) and Virgin and Anguilla Bank (Mattila and Clapham 1989). This survey also identified additional locations in the northeastern Greater Antilles that appear to host densities of humpback whales similar to those detected in better known aggregation areas during the peak of the winter breeding season for this species. These include concentrations of humpback whales off the Turks and Caicos, Great Inagua Island, along the northern coast of Haiti and the Dominican Republic, on the shallow banks to the east and southeast of Anegada Island in the British Virgin Islands, the easternmost banks off St. Croix, and Engaño Bank off the east coast of the Dominican Republic south of the well known aggregation area of Samaná Bay (Mattila et al 1994). The conspicuous absence of humpback whales off the southeastern coast of the Dominican Republic, the nearshore southern Coast of Puerto Rico, and the offshore waters to the south of Puerto Rico remain to be explained. Mattila and Clapham (1989) reported low densities of humpback whales in the Mona Passage

12 compared to the Virgin and Anguilla Banks at peak season, and concluded that the Virgin Bank may be a more important breeding ground than Mona Passage, but considerably less important than Silver Bank. The frequency of acoustic and visual detections of humpback whales observed in this survey in the Mona Passage around Cabo Rojo, Mona Island and Engaño Bank were comparable to those obtained from Silver Bank a few weeks earlier, suggesting that the densities of humpback whales utilizing these areas in the Mona Passage are significant. Similarly, the frequency of acoustic and visual detections of humpback whales to the east and southeast of Anegada Island in the British Virgin islands and to the east of St. Croix suggest that these areas are also utilized by humpback whales in densities similar to those found on Silver Bank. Additional calls were detected to the southeast presumably from whales located on Saba Bank. The 2000 acoustic and visual survey of the waters around St. Kitts and Nevis (Swartz et al. 2001) documented humpback whale calls emanating from the Saba Bank area, further suggesting that this bank may also serve as an aggregation area for wintering humpback whales.

While humpback whales are known to aggregate in the shallow nearshore insular waters and banks of Eastern Caribbean islands, we documented numerous detections of humpback whale calls that appeared to originating from whales located far offshore, over relatively deep water, and not in proximity to any islands or shallow oceanographic features (e.g., sea mounts). Such detections were obtained from sonobuoys deployed along the eastern side of the Turks and Caicos and to the north of the Virgin Islands. We can only speculate that these calling whales were migrating to and/or from the winter aggregation areas in the Greater Antilles, suggesting that humpback singing occurs during migration as well as on aggregation areas near or adjacent to islands. Similar bearings to singing whales apparently far at sea over deep water were obtained south of Puerto Rico. The only land south of Puerto Rico is the small island of Isla Aves located approximately 150 N and 660 W in the middle of the Venezuela Basin. It is not known if humpback whales aggregate at or near this small island or follow the Aves Ridge to the east when migrating up and down the Eastern Caribbean island chain.

Thump Trains: The second most common sound recorded during this survey were Atlantic “thumptrains” or “pulse trains” attributable to minke whales. Such “pulse trains” have been reported by previous researchers (Winn and Perkins 1973) and were recently reviewed by Mellinger et al. (2000) who concluded that the source of these calls were minke whales. We note that while minke whales have been reported from the waters north of Puerto Rico (Mattila and Clapham 1989, Mignucci- Giannoni, 1998, Mullin and Rodin 2000), there have been no recent strandings or observations of minke whales in this region despite the common occurrence of thumptrain calls in recordings made during this survey and other surveys (B. Mase, pers. comm.). Additional thumptrains were frequently recorded during a 2000 survey of the Eastern Caribbean islands of the Lesser Antilles south to Trinidad-Tobago and the North Venezuelan coast (Swartz et al. 2001), and no minke whales were observed during that survey. Given the frequent detections of thumptrains, the number of observer hours achieved during these recent surveys, the lack of observations of minke whales, and the lack of stranded minke whales reported from the Greater and Lesser Antilles, we speculate that the source of these thumptrains is something other than minke whales.

13 Anthropogenic Noise

Ship noise, percussive “explosions”, active sonars, and mechanical sounds of unknown origin were pervasive around Puerto Rico and the Virgin Islands during this survey. It is a well accepted fact that, since the industrial revolution and with the development of steam and fossil fuel driven vessels, the levels of low frequency noise introduced to the marine environment by human industrial and commercial activities has increased above natural sources of low frequency sound (e.g., seismic activity, wind, rain, etc.) by some yet to be measured level (Richardson et al., 1995). It is also generally unknown what the potential long-term effects of chronic exposure to this noise may be on marine life and particularly cetaceans.

Cetaceans evolved sophisticated capabilities to use both passive and active sounds for communication with conspecifics and to explore and navigate in their marine environment. Sensitivity to sound is regarded as the cetaceans’ most highly evolved sensory process (Richardson et al., 1995, Wartzog and Ketten 1999). Humpback whales, for example, have evolved complex acoustic sexual displays that play an important role in their reproductive behavior and biology (Darling 2001), and it is reasonable to consider that some level of background noise would interfere with their ability to communicate and render this aspect of their reproductive behavior ineffective. Similarly, sperm whales and other odontocete cetaceans continuously emit broadband clicking sounds presumably to echolocate while diving to forage for prey and to navigate. At some level, background noise could impede their ability to echolocate effectively.

It will require many years of field observations and other research to determine the levels and duration of exposure to such noise that can be permanently detrimental to cetaceans. In this survey, we were not prepared to measure source levels from such sounds, nor were we able to quantitatively measure recieved sound levels at the hydrophone array or sonobuoys. The sound levels measured relative to the ambient noise field reported in this survey represents an initial starting point with which to document future trends in the use of the waters around Puerto Rico and the Virgin Islands and the kinds and levels of noise in those waters. In the future it will be necessary to undertake additional surveys at regular intervals to develop a baseline of cetacean seasonal distribution and relevant noise levels in the habitats they occupy. To this end, future surveys will need to include the use of calibrated acoustic measurement equipment and employ specific sound measurement methods to document and quantitatively characterize the noise environment in which cetaceans occur, and how that noise environment changes over time.

Autonomous Acoustic Recorders

The two autonomous sea floor recording devices demonstrated a potential for long-term recording to supplement vessel based visual and acoustic survey data. The large magnitude of the acoustic data obtained from these devices, however, will require automated analysis procedures to achieve the maximum benefit from the capabilities of such devices. Manually browsing the continuous stream of files

14 searching for species specific sounds of interest is a time consuming and inefficient process. In the case of blue and fin whales automatic detectors have been developed and work reasonable well. However, in the case of species with more variable calls (e.g., humpbacks), especially in the presence of vessel noise and transient sounds, the operator must go through file by file to pick out the specific sounds to be identified

These results indicated that autonomous recording devices are a viable tool for monitoring over periods of days to months within the region around Puerto Rico and other areas. In the future, units with both higher recording capacity and longer battery life than those used in this survey will be available. Onboard processing (e.g., scheduled sampling rates rather than continuous recording) and increased power efficiency of the electronics circuits will allow for longer recording periods as well as a greater frequency range of acoustic coverage. For example, a unit with a 25GB drive, recording for a total of 12h/day (50% duty cycle) at a sampling rate of 10 kHz can record for almost 20 days. A unit recording at a sampling rate of 5 kHz can record for almost 40 days, while a unit recording at a sampling rate of 2 kHz can record for 90 days. Thus, a suite of 6-10 units deployed around Puerto Rico could provide circum-island coverage for over a month, depending on the sampling rate and duty cycle. If numbers and distributions of animals in a specific area were of interest, sets of recording devices could be deployed in arrays, where array spacing is primarily determined by the frequency and source level of the primary species of interest. A minimum of three recording devices are needed for such an array, however four or more units are recommended. For example, with fin whales spacing on the order of 5 miles can be used since sounds from the same fin whale are readily detected out to ranges of tens of miles. For higher frequency species, such as pilot whales or dolphin, array spacing would need to be on the order of 500-1000m.

Ultimately autonomous bottom recorders will provide a relatively cost effective mechanism for sampling a broad area for an extended period of time. A drawback to this technique is that one must wait until the units are recovered and the data analyzed before one learns anything from the effort. If real-time results are not critical, and one knows the time period and the area of interest, a dispersed set of recording devices is a very effective mechanism for acoustic data collection. Real-time or near real-time monitoring could be achieved by integrating autonomous recording devices with various types of sea- buoys that gather oceanographic and weather data and transmit those data by radio to a shore based laboratory, much like a sonobuoy.

Future Surveys

The low sighting rates for some of the cetacean species could be the result of the reduced length of the survey track necessitated to accommodate active naval exercises in many of the areas to the north and south of Puerto Rico. The original survey design was based on estimates of encounter rates for the most common species, and should have resulted in sufficient sightings of those species to serve as the basis for statistical estimation of abundance with coefficients of variation ranging from 0.20-0.30. Future survey effort (i.e., km of trackline searched) of this region should be based on the sighting rates

15 obtained in this survey and be of sufficient length to allow an increase in encounter rates to achieve the desired statistical precision for estimates of abundance. Such a survey would involve increasing the tracklines to approximately 6,400 km to cover the areas from nearshore to the 5000 m bathymetric depth contour around Puerto Rico. Based on the results from the 2001 survey, this effort estimate should result in at least 82 primary humpback whale group sightings compared to 31 sightings on the Puerto Rican Bank in this survey, and an abundance estimate based on these sightings would have an expected coefficient of variation of 0.20 or less (Fig. 24). Aerial surveys flown during the vessel survey could provide additional estimates of group size and expand the range of the vessel survey and verify both acoustic and visual detections of whales.

The sounds recorded from various cetacean species during this survey established the beginning of species specific sound archive. Future surveys will contiribute additional species specific calls and sounds as these are obtained and verified by visual observations. These data will be the foundation for idenifying sounds of unknown origin, and for identifying and enumerating cetacean sounds recorded when visual observations are not possible (e.g., during poor weather, at night, and data from autonomous recording devices). To achieve this capability, additional resources need to be devoted to onging archiving of species specific sounds recorded in specific locations, and the development of "recognition" software to compare and match sounds of unknown origin with those from known sources. Ideally, year round acoustic monitoring of key locations on the Puerto Rican Bank (e.g., the Mona Passage, the Virgin Passage) would provide presence and absence information for specific cetacean species that could serve as an index of their seasonal arrival, residence, and departure from this region. Such acoustic monitoring could be conducted from small vessels, from bottome mounted recorders or hydrophone arrays cabled to shore, or some combination of acoustic montioring methods.

Similarly, anthropogenic sound and noise recorded during this survey will surve as a baseline measurement of the variety and location of this noise with which to monitor the acoustic environment in future years as trends in commercial shipping and other human activities continue.

16 ACKNOWLEDGEMENTS

We wish to thank our fellow researchers and observers for their dedication and efforts to find cetaceans in what was often less than ideal conditions. We were pleased to have worked with Bret Elkind, Aaron Thode, Kathy Foley, Erin Oleson, Joe Contillo, Grisel Rodríguez, Diana Mora, Marta Rodríguez, Mayela Alsina, Vera Rosado, Suranahi Buglass, Lanora Lang, Paul Damman, Carrie Hubbard, Andre Debose, María Cardona, Liza Guzmán, José Pérez, and Eric Zolman. We also want to thank the officers and crew of the NOAA ship Gordon Gunter and the support staff at the SEFSC Pascagoula Laboratory for their assistance throughout. Our colleagues Jay Barlow, John Hildebrand, Mark McDonald, Charles Greene and Dave Mellinger provided critical advice and software development for the acoustic systems used for the detection and tracking of whales. Vessel clearance to conduct the survey in their territorial waters was obtained from the governments of the Bahamas, the Turks and Caicos, Haiti, Dominican Republic, and the British Virgin Islands. Research permits for the waters of Puerto Rico were issued by Puerto Rico's Departamento de Recursos Naturales y Ambientales. The survey was conduced under the SEFSC’s U.S. Marine Mammal Protection Act Research Permit No. 779-1339 issued by the NOAA Fisheries Office of Protected Resources, Silver Spring, Maryland USA. This survey was supported by the Chief of Naval Operations, Environmental RDT & E Program (Code N45) under an Interagency Agreement with NOAA Fisheries’ Southeast Fisheries Science Center.

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21 List of Tables:

Table 1. Number of cetacean groups (n), mean group size, water depth, and sea surface temperature for sightings along the eastern Bahamas, Puerto Rico, and the Virgin Islands from 12 February to 8 March 2001.

Table 2. Summary of cetacean sightings along the eastern side of the Bahamas, Puerto Rico, and the Virgin Islands from February 12 to 8 March 2001 (S = effort status of sighting, SST = sea surface temperature).

Table 3. Acoustic data obtained from sonobuoys and during hydrophone array tows from February 12 to March 8, 2001 along the eastern side of the Bahamas, and around Puerto Rico and the Virgin Islands.

Table 4. Percussive "explosion-like" sounds detected on sonobuoys and during hydrophone array tows from February 12 to March 8, 2001 around Puerto Rico and the Virgin Islands.

List of Figures:

Figure 1. NOAA ship Gordon Gunter.

Figure 2. Survey tracklines from Abaco Island, Bahamas south to Puerto Rico and the Virgin Islands (solid black line).

Figure 3. Marine mammal observers at the “big-eye” 25x binoculars.

Figure 4. Illustration of a typical DIFAR sonobuoy utilized in the survey.

Figure 5. A 3-D plot showing signal intensity as a function of frequency and bearing angle from 00 to 3600, showing a single calling whale at a bearing of 101 degrees magnetic from the sonobuoy’s location with major sound energy between 450 Hz and 650 Hz.

Figure 6. Illustration of the towed 5-element hydrophone array and the signal monitoring and tracking equipment utilized in the survey.

Figure 7. An autonomous bottom acoustic recording device or “pop-up” buoy developed by C. Clark at Cornell University and deployment operations for one device placed in the Mona Channel.

Figure 8. An example of the recordings from one autonomous bottom recording device or "pop-up" developed by C. Clark of Cornell University. The spectrogram shows sound energy (spectrum level)

22 versus time of day (GMT) recorded on February 19, 2001 in Mona Chanel. The sound energy peaks represent close approaches by passing vessels. Marine mammal sounds, mostly humpback whale calls, are also embedded in these data.

Figure 9. Sightings of humpback whales (triangles, n=72 ) during visual surveys (solid black lines) along the eastern and southern sides of the Bahamas south to Puerto Rico and the Virgin Islands.

Figure 10. Sightings of dolphins during visual surveys (black lines): Steno bredanensis (star, n=1), Tursiops truncatus (triangle, n=2), Stenella attenuata (circles, n= 3), Stenella frontalis (squares, n=10), and Stenella longirostris (diamonds, n=2).

Figure 11. Sightings of odontocete whales during visual surveys (black lines): Physeter macrocephalus (circles, n=5), Ziphius cavirostris (triangles, n=3), Mesoplodon spp. (squares, n=3), Pseudorca crassidens (star, n=1), and Globicephala cf. macrorhynchus. (diamonds, n=8).

Figure 12. Survey track lines along the eastern side of the Bahamas, around Puerto Rico and the Virgin Islands (black line) showing location of sonobuoy drops (circles with radials) and hydrophone array tows (bold lines).

Figure 13. Survey track lines along the eastern side of the Bahamas, the Turks and Caicos, Mouchoir, Silver and Navidad Banks (thin line) showing location of sonobuoy drops with magnetic bearings to calling humpback whales (circles with radials).

Figure 14. Acoustic detections of humpback whales during surveys to the north of Puerto Rico and the Virgin Islands showing the location of sonobuoy drops and magentic bearings to singing humpback whales (circles with radials).

Figure 15. Acoustic detections of humpback whales during surveys to the south of Puerto Rico and the Virgin Islands showing the location of sonobuoy drops with magnetic bearings to singing humpback whales (circles with radials), and the location of one autonomous acoustic recording device is idicated by a i.

Figure 16. Acoustic detections of humpback whales during surveys to the west, and southwest of Puerto Rico showing the location of sonobuoy drops with magnetic bearings to singing humpback whales (circles with radials).

Figure 17. Acoustic detections of humpback whales during surveys to the west, northwest of Puerto Rico showing the location of sonobuoy drops with magnetic bearings to singing humpback whales (circles with radials), and the location of one autonomous acoustic recording device is idicated by a i.

23 Figure 18. Location of acoustic detections of sperm whales (n = 12) made by sonobuoys and during hydrophone array tows around Puerto Rico and the Virgin Islands.

Figure 19. Location of 79 of 135 sonobuoys (circles) that detected Atlantic thumptrains throughout the study area between 12 February and 12 March 2001.

Figure 20. Spectrogram of a typical Atlantic "thumptrain" recorded during the February-March marine mammal survey around Puerto Rico and the Virgin Islands. The thumptrain consists of a 1-2 minute series of discrete repetitive pulses that increase in intensity and frequency, and terminate abruptly. Major sound energy is centered between 250 Hz and 650 Hz.

Figure 21. Locations where percussive "explosion-like" sounds were detected by sonobuoys and during towed hydrophone array sampling (circles). Radials from circles indicate magentic bearings to the sources of the percussive sounds.

Figure 22. A spectrogram of a percussive "explosion-like" sound recorded off the south coast of Puerto Rico on 27 February 2001. Sound energy between 100 Hz and 20 kHz (upper line) averaged approximately 26.86 dB above the ambient noise level (lower line) in the area just prior to the occurrence of the percussive sound.

Figure 23. The location along the survey trackline (thin line) where commercial ship noise was detected (circles) by sonobuoys and during towed hydrophone array sampling (bold lines).

Figure 24. A proposed track line around Puerto Rico for future acoustic and visual surveys based on the marine mammal sighting rates and acoustic detections obtained during the Febraury-March 2001 survey.

24 Table 1. Number of cetacean groups (n), mean group size, water depth, and sea surface temperature for sightings along the eastern Behamas, Puerto Rico, and the Virgin Islands from 12 February to 8 March 2001.

Group Size Water Depth Sea Surface Temperature (meters) (0C) Species n Mean (SE) Mean (SE) Range Mean (SE) Range Range Megaptera novaeangliae 72 1.8 (0.15) 1 - 1395 (167) 34 -6948 26.2 (0.43) 25.3 - 27.7 10 Physeter macrocephalus 6 3.3 (0.98) 1 - 7 2531 (802) 680 - 4817 26.0 (0.31) 24.6 - 26.7 Ziphius cavirostris 1 3.0 2872 26.5 Mesoplodon spp. 3 1.6 (0.66) 1 - 3 2515 (1145) 537 -4506 26.5 (0.21) 26.3 - 27.0 Pseudorca crassidens 1 9.0 3103 26.8 Globicephala 8 12.5 (1.88) 6 - 2556 (770) 806 -7041 25.9 (0.26) 24.2 - 26.8 macrorhynchus 20 Steno bredanensis 1 3.0 7226 26.0 Tursiops truncatus 2 6.0 (3.0) 3 - 9 1662 (1210) 452 -2872 26.8 (0.30) 26.5 - 27.1 Stenella spp. 1 2.0 1019 26.9

Stenella attenuata 3 12.6 (3.9) 5 - 18 3655 (1916) 663 -7226 26.1 (0.37) 25.5 - 26.8 Stenella frontalis 10 22.3 (4.6) 1 - 54 2547 (548) 452 -4499 26.7 (0.13) 26.0 - 27.4 Stenella longirostris 2 95.0 (35.0) 60 - 130 805 (36) 768 -841 26.7 (0.25) 26.5 - 27.0 Unidentified dolphin 11 11.6 (8.7) 1 - 99 1768 (655) 51 -7041 26.5 (0.13) 26.0 - 27.1

25 Group Size Water Depth Sea Surface Temperature (meters) (0C) Species n Mean (SE) Mean (SE) Range Mean (SE) Range Range Unidentified small whale 3 1.0 1 - 1 3451 (952) 1760 -5054 26.6 (0.32) 26.2 - 27.3 Unidentified large whale 13 1.2 (0.1) 1 - 2 1451 (348) 340 -4280 26.4 (0.14) 25.7 - 27.9 Unidentified ziphiid 2 1.0 1 - 1 4091 (2579) 1512 -6670 26.6 (0.30) 26.3 - 26.9 Unidentified odontocete 3 1.3 (0.3) 1 - 2 1565 (479) 628 -2206 27.1 (0.33) 26.8 - 27.7

26 Table 2. Summary of cetacean sightings during NOAA Ship Gordon Gunter Cruise GU-01-01 in the Atlantic and Caribbean Sea, Legs 1 and 2 February 6 - March 14, 2001 (S = effort status of sighting, SST = Sea surface temperature).

Date Species Group Position (N,W) SST Depth (0C) (m) 2001 Feb 10 Physeter macrocephalus 1 26°03' 78°29' 24.6 672 2001 Feb 11 Globicephala cf. macrorhynchus 19 24°41' 77°39' 24.2 1244 2001 Feb 15 Megaptera novaeangliae 1 21°06' 70°14' 25.9 4141 2001 Feb 15 Megaptera novaeangliae 1 21°04' 70°09' 25.9 3157 2001 Feb 15 Megaptera novaeangliae 1 21°00' 70°01' 25.9 2086 2001 Feb 15 Megaptera novaeangliae 2 21°00' 70°00' 26.0 2086 2001 Feb 15 Megaptera novaeangliae 2 21°00' 70°01' 26.0 2086 2001 Feb 15 Megaptera novaeangliae 2 20°58' 69°58' 26.0 2086 2001 Feb 15 Megaptera novaeangliae 1 20°58' 69°57' 26.0 2086 2001 Feb 15 Megaptera novaeangliae 1 20°58' 69°56' 26.0 2086 2001 Feb 15 Megaptera novaeangliae 2 20°57' 69°56' 26.0 2086 2001 Feb 15 Megaptera novaeangliae 1 20°55' 69°51' 26.0 1281 Megaptera novaeangliae 1 2001 Feb 15 Megaptera novaeangliae 1 20°55' 69°50' 26.0 1281 2001 Feb 15 Megaptera novaeangliae 1 20°54' 69°49' 26.0 1281 2001 Feb 15 Megaptera novaeangliae 1 20°54' 69°49' 26.0 1281 2001 Feb 15 Megaptera novaeangliae 2 20°54' 69°48' 26.0 1281 2001 Feb 15 Megaptera novaeangliae 1 20°53' 69°48' 26.0 1281 2001 Feb 15 Megaptera novaeangliae 1 20°53' 69°48' 26.0 1281 2001 Feb 15 Megaptera novaeangliae 2 20°52' 69°45' 26.0 1601 2001 Feb 15 Megaptera novaeangliae 1 20°50' 69°41' 26.0 1491 2001 Feb 15 Megaptera novaeangliae 1 20°50' 69°40' 26.0. 1669 2001 Feb 15 Unidentified large whale 1 20°48' 69°37' 26.0 1669 2001 Feb 15 Megaptera novaeangliae 1 20°46' 69°34' 26.1 3020 2001 Feb 15 Megaptera novaeangliae 1 20°46' 69°32' 26.1 3221 2001 Feb 15 Megaptera novaeangliae 1 20°38' 69°18' 26.1 2626 2001 Feb 15 Megaptera novaeangliae 1 20°38' 69°16' 26.1 2626

27 Date Species Group Position (N,W) SST Depth (0C) (m) 2001 Feb 15 Unidentified large whale 1 20°32' 69°10 26.0 2582 2001 Feb 15 Megaptera novaeangliae 4 20°32' 69°10' 26.0 2582 2001 Feb 15 Megaptera novaeangliae 2 20°29' 69°08' 26.0 2167 2001 Feb 15 Megaptera novaeangliae 1 20°28' 69°06' 26.1 185 2001 Feb 15 Megaptera novaeangliae 4 20°27' 69°05' 26.1 185 2001 Feb 15 Megaptera novaeangliae 2 20°22' 69°00' 26.3 1610 2001 Feb 15 Megaptera novaeangliae 1 20°14' 68°51' 26.3 1098 2001 Feb 15 Unidentified large whale 1 20°13' 68°49' 26.3 1098 2001 Feb 15 Unidentified large whale 1 20°12' 68°49' 26.0 1034 2001 Feb 15 Unidentified large whale 1 20°11' 68°47' 26.3 1007 2001 Feb 15 Unidentified large whale 1 20°11' 68°48' 26.3 1007 2001 Feb 15 Megaptera novaeangliae 1 20°11' 68°48' 26.3 1007 2001 Feb 16 Unidentified large whale 2 18°21' 67°44' 26.6 337 2001 Feb 16 Megaptera novaeangliae 1 18°18' 67°41' 26.5 2776 2001 Feb 16 Unidentified large whale 2 18°14' 67°37' 26.5 377 2001 Feb 16 Megaptera novaeangliae 1 18°04' 67°28' 26.6 293 2001 Feb 16 Stenella attenuata 5 18°01' 67°25' 26.8 655 2001 Feb 17 Unidentified dolphin 2 18°29' 65°09' 26.0 51 2001 Feb 17 Megaptera novaeangliae 2 18°31' 65°08' 26.0 55 2001 Feb 17 Megaptera novaeangliae 2 18°33' 65°05' 26.1 68 2001 Feb 17 Unidentified dolphin 1 18°45' 64°47' 26.0 68 2001 Feb 17 Physeter macrocephalus 7 18°59' 64°48' 26.5 3294 2001 Feb 17 Tursiops truncatus 3 18°58' 65°07' 26.5 2837 2001 Feb 18 Globicephala cf. macrorhynchus 7 19°01' 65°18' 26.1 3660 2001 Feb 18 Stenella attenuata 18 19°14' 65°27' 26.0 7137 Steno bredanensis 3 2001 Feb 18 Unidentified Ziphiidae 1 19°15' 65°31' 26.3 6588 2001 Feb 22 Megaptera novaeangliae 2 20°34' 64°43' 26.1 5033

28 Date Species Group Position (N,W) SST Depth (0C) (m) 2001 Feb 23 Physeter macrocephalus 1 20°25' 64°20' 26.1 4758 2001 Feb 23 Unidentified dolphin 3 19°46' 65°02' 26.0 6954 Globicephala cf. macrorhynchus 10 2001 Feb 23 Megaptera novaeangliae 2 19°43' 65°09' 26.2 6863 2001 Feb 24 Stenella frontalis 12 17°22' 66°07' 26.6 4443 2001 Feb 26 Mesoplodon sp. 1 16°04' 65°46' 26.4 4451 2001 Feb 27 Stenella frontalis 25 16°19' 66°11' 26.4 4357 2001 Feb 27 Stenella frontalis 22 16°45' 66°19' 26.6 4379 2001 Feb 27 Physeter macrocephalus 5 17°03' 66°24' 26.7 4575 2001 Feb 27 Unidentified dolphin 2 17°05' 66°21' 26.6 4548 2001 Feb 28 Stenella frontalis 37 17°33' 66°33' 26.5 3338 2001 Feb 28 Unidentified Ziphiidae 1 17°44' 66°36' 26.9 1493 2001 Feb 28 Unidentified dolphin 1 17°46' 66°37' 26.9 1493 2001 Feb 28 Tursiops truncatus 9 17°51' 66°39' 27.1 447 Stenella frontalis 1 2001 Feb 28 Stenella frontalis 20 7°52' 66°43' 26.9 1007 Stenella attenuata 2 2001 Feb 28 Stenella frontalis 15 17°49' 66°48' 27.2 1135 2001 Feb 28 Unidentified small whale 1 17°45' 66°52' 27.3 1739 2001 Feb 28 Unidentified dolphin 1 17°43' 66°53' 26.0 2233 2001 Feb 28 Stenella attenuata 15 17°38' 67°00' 25.5 3038 2001 Mar 01 Globicephala cf. macrorhynchus 6 17°33' 67°06' 26.0 3825 2001 Mar 01 Unidentified large whale 1 17°26' 67°07' 25.7 3488 2001 Mar 01 Stenella frontalis 12 17°20' 67°15' 26.4 3967 2001 Mar 01 Pseudorca crassidens 9 17°30' 67°43' 26.8 3065 2001 Mar 01 Mesoplodon sp. 1 17°43' 67°28' 27.0 2471 2001 Mar 02 Megaptera novaeangliae 3 17°57' 67°25' 26.5 717 2001 Mar 02 Stenella longirostris 130 17°57' 67°25' 26.5 831 2001 Mar 02 Megaptera novaeangliae 3 18°03' 67°26' 26.4 210 2001 Mar 02 Megaptera novaeangliae 1 18°05' 67°26' 26.4 179

29 Date Species Group Position (N,W) SST Depth (0C) (m) 2001 Mar 02 Unidentified large whale 1 18°03' 67°42' 26.7 699 2001 Mar 02 Unidentified large whale 1 18°04' 67°45' 27.9 578 2001 Mar 02 Stenella frontalis 25 18°04' 67°45' 26.0 699 2001 Mar 02 Megaptera novaeangliae 2 18°07' 67°48' 26.7 518 2001 Mar 02 Megaptera novaeangliae 1 18°10' 67°53' 26.8 273 2001 Mar 02 Unidentified large whale 1 18°07' 68°00' 26.7 536 2001 Mar 02 Physeter macrocephalus 4 18°06' 68°01' 26.6 798 2001 Mar 02 Physeter macrocephalus 2 18°01' 67°59' 26.0 904 2001 Mar 02 Unidentified large whale 2 17°56' 68°05' 26.6 4227 2001 Mar 03 Megaptera novaeangliae 4 18°30' 68°14' 26.0 110 2001 Mar 03 Megaptera novaeangliae 1 18°32' 68°11' 26.5 178 2001 Mar 03 Megaptera novaeangliae 3 18°32' 68°11' 26.4 178 2001 Mar 03 Megaptera novaeangliae 2 18°32' 68°03' 26.6 86 2001 Mar 03 Megaptera novaeangliae 10 18°32' 68°08' 26.6 59 2001 Mar 04 Globicephala cf. macrorhynchus 20 18°21' 67°35' 26.0 796 2001 Mar 04 Unidentified dolphin 4 18°20' 67°27' 26.7 844 2001 Mar 04 Unidentified dolphin 9 18°20' 67°23' 27.1 604 2001 Mar 04 Megaptera novaeangliae 3 18°23' 67°17' 26.6 254 2001 Mar 04 Megaptera novaeangliae 3 18°32' 67°10' 26.6 59 2001 Mar 04 Megaptera novaeangliae 1 18°32' 67°07' 26.4 55 2001 Mar 04 Megaptera novaeangliae 1 18°35' 67°03' 26.5 361 2001 Mar 04 Megaptera novaeangliae 1 18°39' 67°09' 26.3 1098 2001 Mar 05 Unidentified small whale 1 18°49' 67°23' 26.2 4992 2001 Mar 05 Ziphius cavirostris 3 18°52' 66°56' 26.5 2837 2001 Mar 05 Megaptera novaeangliae 2 18°47' 66°53' 26.0 2681 2001 Mar 05 Globicephala cf. macrorhynchus 15 18°36' 66°43' 26.0 1336 2001 Mar 06 Globicephala cf. macrorhynchus 14 18°38' 66°42' 26.3 1546 2001 Mar 06 Unidentified odontocete 1 18°46' 66°18' 26.8 2180 2001 Mar 06 Unidentified odontocete 2 18°44' 66°16' 27.7 1837 2001 Mar 06 Megaptera novaeangliae 4 18°42' 66°11' 27.7 1636

30 Date Species Group Position (N,W) SST Depth (0C) (m) 2001 Mar 06 Stenella frontalis 54 18°39' 66°06' 27.4 1385 2001 Mar 06 Unidentified dolphin 4 18°39' 66°01' 27.1 1290 2001 Mar 06 Megaptera novaeangliae 2 18°37' 65°58' 27.1 1096 2001 Mar 06 Stenella longirostris 60 18°33' 65°48' 27.0 759 2001 Mar 06 Megaptera novaeangliae 2 18°32' 65°48' 27.0 728 2001 Mar 06 Unidentified odontocete 1 18°31' 65°47' 27.0 620 2001 Mar 07 Megaptera novaeangliae 2 18°33' 64°44' 26.0 46 2001 Mar 07 Megaptera novaeangliae 2 18°38' 64°38' 26.3 37 2001 Mar 07 Megaptera novaeangliae 2 18°40' 64°38' 25.3 37 2001 Mar 07 Megaptera novaeangliae 2 18°42' 64°38' 26.3 34 2001 Mar 07 Megaptera novaeangliae 1 18°49' 64°37' 26.3 732 2001 Mar 07 Megaptera novaeangliae 1 18°47' 64°17' 26.6 487 2001 Mar 07 Megaptera novaeangliae 1 18°45' 64°14' 26.6 408 2001 Mar 07 Unidentified dolphin 2 18°44' 64°07' 26.5 366 2001 Mar 07 Megaptera novaeangliae 1 18°43' 64°03' 26.5 739 2001 Mar 07 Unidentified small whale 1 18°46' 63°53' 26.5 3495 2001 Mar 07 Megaptera novaeangliae 1 18°46' 63°42' 26.4 6101 2001 Mar 08 Megaptera novaeangliae 5 18°23' 64°06' 26.3 441 2001 Mar 08 Mesoplodon sp. 3 18°20' 64°11' 26.3 531 2001 Mar 08 Megaptera novaeangliae 1 18°11' 64°23' 26.6 1373 2001 Mar 08 Unidentified dolphin 1 18°09' 64°25' 26.7 763 2001 Mar 08 Megaptera novaeangliae 1 17°50' 64°31' 26.8 822 2001 Mar 08 Megaptera novaeangliae 2 17°50' 64°29' 26.8 818 2001 Mar 08 Megaptera novaeangliae 3 17°47' 64°25' 26.9 897 2001 Mar 08 Megaptera novaeangliae 2 17°45' 64°28' 26.8 1135 2001 Mar 08 Globicephala cf. macrorhynchus 9 17°40' 64°33' 26.8 840

31 Table 3. Acoustic data obtained from sonobuoys and during hydrophone array tows from February 12 to March 8, 2001 along the eastern side of the Bahamas, and around Puerto Rico and the Virgin Islands.

Buoy Date Time DAT Depth Depth LAT LONG Bearing Bearing Bearin Thump MM Anthro. No. (UTC) Tape (M) (M) (DD) (DD) No. 1 No. 2 g No. 3 . Tr. Species Noise

SB-07 2/13/01 1439 01-06 303 4800 25.0173 -75.3982 1 SB-08 2/13/01 1833 01-07 303 4600 24.6873 -74.9740 1 SB-09 2/13/01 2213 01-08 121 5151 24.3829 -74.5812 1 10 SB-10 2/14/01 857 01-09 303 4400 23.2450 -73.5380 267 1 9 SB-11 2/14/01 943 01-09 303 4400 23.1569 -73.4674 1 9 SB-12 2/14/01 1110 01-10 27 3000 22.9881 -73.3287 1 9 SB-13 2/14/01 1328 01-10 121 3800 22.7272 -73.1126 127 134 145 1 9 SB-14 2/14/01 1645 01-11 27 2900 22.4715 -72.7037 205 198 1 9 SB-18 2/14/01 1953 01-12 27 4000 22.2485 -72.2868 1 9 1 SB-19 2/14/01 2149 01-13 27 3220 22.1124 -72.0303 190 105 58 1 9, 60 SB-22 2/14/01 29 01-13 27 2500 21.9240 -71.6765 0 9 1 SB-25 2/14/01 359 01-14 27 1400 21.7095 -71.1915 190 176 259 1 9 SB-26 2/15/01 929 01-14 27 4000 21.2627 -70.4859 204 170 240 0 9 SB-27 2/15/01 1125 01-15 27 4000 21.1092 -70.2279 170 228 300 1 9 SB-30 2/15/01 1618 01-15 27 3475 20.7705 -69.5409 10 280 310 1 9 SB-31 2/15/01 1953 01-16 27 1500 20.4456 -69.0815 100 235 195 1 9 SB-32 2/15/01 138 01-17 27 4200 19.8333 -68.4367 340 272 20 1 9 SB-33 2/16/01 448 01-17 27 6500 19.3854 -68.2217 80 160 225 1 9 1 SB-34 2/16/01 713 01-18 27 1870 19.0421 -68.0549 200 67 1 9 1 SB-35 2/16/01 1144 01-18 27 232 18.4154 -67.7582 280 225 80 0 9 SB-37 2/16/01 1522 01-20 27 239 18.2252 -67.6147 0 SB-39 2/16/01 1709 01-21 27 100 18.0250 -67.4330 8 14 1(?) 9, 60 SB-40 2/16/01 1751 01-21 27 243 17.9436 -67.3634 0 SB-41 2/17/01 753 01-22 27 450 18.0932 -65.2937 0 SB-43 2/17/01 915 01-22 34 18.1524 -65.2191 0 SB-44 2/17/01 1100 01-23 27 80 18.3916 -65.0887 40 302 330 1 9 SB-46B 2/17/01 1401 01-24 300 18.6998 -64.8681 31 0 9 SB-47 2/17/01 1648 01-25 121 2900 18.9719 -64.7969 360 1 9, 10, 60 SB-48 2/17/01 1909 01-25 121 3630 19.2136 -65.0182 343 280 1 9, 60 1, 4 SB-49 2/17/01 1958 01-26 27 2835 19.0637 -65.0850 173 125 200 1 9, 60

32 SB-50 2/17/01 129 01-27 27 84 18.5276 -65.3209 165 205 244 9 1 SB-51 2/18/01 1008 01-28 27 2650 18.8995 -65.2633 155 238 195 1 9 SB-52 2/18/01 1146 01-28 27 2000 19.0463 -65.3432 1 9, 10, 26 SB-54 2/18/01 1438 01-29 27 6584 19.2420 -65.5588 1 9 1 SB-55 2/18/01 1524 01-29 121 3650 19.1397 -65.5950 350 1 9 SB-56 2/18/01 1745 01-30 27 2000 18.7706 -65.7470 1 SB-57 2/18/01 106 01-30 27 5500 19.1878 -66.0708 145 36 1 9, 60 SB-57B 2/18/01 215 01-31 27 5500 19.1878 -66.0708 10 350 0 9 1 SB-58 2/22/01 1319 01-33 27 5000 20.9835 -65.6354 330 20 270 1 9 SB-59 2/22/01 1415 01-33 27 5000 20.9205 -65.4938 323 0 9 3 SB-60 2/22/01 1502 01-33/3 27 5000 20.8725 -65.3785 310 22 260 0 9, 10 SB-61 2/22/01 1630 01-34 27 5000 20.7771 -65.1606 330 273 63 1 9 SB-62 2/22/01 1827 01-35 27 5000 20.6437 -64.8656 1 9 SB-63 2/22/01 2121 01-35 27 5000 20.4713 -64.5086 270 90 345 1 9 SB-64 2/23/01 1128 01-37 27 5500 20.4167 -64.3167 0 9, 10 SB-65 2/23/01 1240 01-37/3 27 5500 20.3003 -64.0795 20 50 150 1 9, 60 SB-66 2/23/01 1517 01-38/3 27 5500 20.0932 -64.4917 120 148 280 1 9 3 SB-67 2/23/01 1730 01-39 27 5500 19.9068 -64.8545 65 310 0 9 3 SB-73 2/23/01 2010 01-40 2900 19.7429 -65.1358 345 20 194 0 9 SB-74 2/23/01 2228 01-41 27 6590 19.5840 -65.4727 226 22 192 0 9 SB-75 2/24/01 1048 01-42 27 3800 17.8260 -65.4310 184 155 192 0 9 SB-76 2/24/01 1249 01-42 27 1200 17.6710 -65.7623 145 191 0 9, 10 SB-77 2/24/01 1424 01-43 121 2900 17.5635 -66.0260 1 9 SB-78 2/24/01 1512 01-44/4 3657 17.4963 -66.1535 117 121 139 1 9 SB-79 2/24/01 1756 01-45 27 5000 17.3148 -65.9815 94 138 1 9 SB-80 2/24/01 1944 01-45/4 27 4750 17.1568 -65.7057 0 9 SB-81 2/24/01 2134 01-46 27 4575 17.0086 -65.4349 301 17 1 9 5 SB-82 2/25/01 1104 01-47 27 1600 17.6130 -65.2113 282 24 0 9 5 SB-83 2/25/01 1229 01-47/4 27 1000 17.7346 -65.0341 0 9 SB-84 2/25/01 1327 01-48 121 2500 17.8157 -64.9116 0 SB-85 2/25/01 1344 01-48 27 3300 17.8392 -64.8764 0 SB-86 2/25/01 1450 01-48 27 4300 17.9283 -64.9712 0 10 5 SB-87 2/25/01 1528 01-49 27 4200 17.9814 -65.0737 44 270 1 9 5 SB-88 2/25/01 1852 01-50 27 22 18.1672 -65.2732 0 SB-89 2/25/01 218 01-50 27 2000 17.5340 -65.2888 290 93 140 1 9 3, 5 SB-91 2/25/01 449 01-52 27 4400 17.3179 -65.3101 ? ?

33 SB-91B 2/25/01 1047 01-53 27 4400 17.0000 -65.0000 ? ? SB-92 2/26/01 1200 01-53/5 27 4900 16.9765 -65.3154 165 0 9 5 SB-93 2/26/01 1439 01-54 27 5400 16.5800 -65.5214 80 1 9 3, 5 SB-94 2/26/01 1741 01-55 27 5500 16.1249 -65.7588 1 9 3, 5 SB-95 2/26/01 1807 01-55 121 6000 16.0682 -65.7905 1 9 2, 3 SB-96 2/26/01 2103 01-56 27 5500 15.6612 -65.9960 55 26 195 1 9 2 SB-97 2/27/01 1256 01-57 27 5400 16.1382 -66.1447 70 50 1 9 SB-99 2/27/01 1735 01-58 27 5000 16.8028 -66.3195 330 0 9 2 SB-100 2/27/01 2043 01-59/6 27 5000 17.1006 -66.3807 325 90 0 9, 10 2 SB-101 2/28/01 1115 01-61 27 5000 17.0042 -66.2530 65 85 335 0 9 5 SB-102 2/28/01 1331 01-62 27 5000 17.2771 -66.4778 95 0 9, 10, 36 2, 3 SB-103 2/28/01 1612 01-62 27 3336 17.6317 -66.5830 100 291 0 9 1 SB-104 2/28/01 2123 01-63 27 2210 17.7250 -66.9067 110 1 9 SB-105 3/1/01 1125 01-64 27 3200 17.5575 -67.1158 70 330 1 9 2 SB-106 3/1/01 1249 01-64 121 3300 17.3853 -67.1220 0 9 SB-107 3/1/01 1304 01-64/6 27 5000 17.3453 -67.1233 350 336 110 1 9 1 SB-108 3/1/01 1550 01-66 27 3500 17.3981 -67.4799 350 345 5 1 9 2 SB-109 3/1/01 1730 01-67 121 3000 17.0000 -68.0000 1 9 1 SB-110 3/1/01 1740 01-67 27 3000 17.4833 -67.7602 10 355 5 1 9 SB-111 3/1/01 1905 01-67/6 2700 18.0000 -68.0000 4 1 9, 10, 36 1 SB-112 3/1/01 2055 01-69 27 2700 17.6428 -67.5875 355 10 0 9 1 SB-113 3/2/01 1106 01-70 27 1636 17.8382 -67.3233 355 340 320 1 9 SB-114 3/2/01 1206 01-70/7 27 825 17.9717 -67.4346 331 136 345 0 9 1, 3 SB-115 3/2/01 1437 01-71/7 27 311 18.1853 -67.4614 331 325 342 0 9 3 SB-116 3/2/01 1623 01-72/7 27 400 18.0651 -67.7275 320 297 120 1 9 3 SB-117 3/2/01 1902 01-73/7 27 70 18.1782 -67.9567 120 335 280 0 9 SB-118 3/2/01 2028 01-74/7 27 1100 17.9758 -67.9820 79 360 355 0 9, 10 SB-119 3/3/01 1015 01-75 27 790 18.0972 -68.0563 14 75 345 0 9 SB-120 3/3/01 1318 01-76 27 2300 17.8544 -68.3570 60 90 20 1 9 SB-121 3/3/01 1545 01-76/7 27 750 18.2157 -68.5002 90 100 125 1 9 SB-123 3/3/01 1835 01-77 27 60 18.5469 -68.1896 160 325 275 1 9 SB-127 3/3/01 2204 01-80/8 27 460 18.4789 -67.7338 312 280 360 0 9 SB-129 3/4/01 845 01-82 27 350 18.4363 -67.8734 307 111 280 1 9 SB-130 3/4/01 1255 01-83 27 235 18.3731 -67.7416 355 115 1 9 SB-131 3/4/01 2202 01-84/8 27 1100 18.6752 -67.1749 215 20 120 0 9 SB-135 4/5/01 1222 01-86 27 5050 18.8699 -67.4661 265 120 257 1 9

34 SB-136 3/5/01 1405 01-87 27 3000 19.0032 -67.6012 150 95 235 1 9 1 SB-137 3/5/01 1550 01-88 27 4345 18.9973 -67.3100 0 9 1 SB-138 3/5/01 1744 01-88 27 4056 19.0000 -67.0002 330 170 257 1 9 SB-140 3/5/01 1949 01-89 27 1900 18.7137 -66.8556 300 190 296 0 9 SB-141 3/6/01 1108 01-89/9 27 1700 18.6625 -66.6964 255 80 297 1 9 SB-142 3/6/01 1325 01-90 27 4500 18.9870 -66.5070 70 250 120 1 9 SB-143 3/6/01 1643 01-91 27 1240 18.6789 -67.1511 266 122 165 1 9 3 SB-144 3/7/01 1047 01-92 27 55 18.4952 -64.8620 225 195 204 0 9 SB-145 3/7/01 1209 01-92/9 27 50 18.6197 -64.6541 20 5 193 1 9 1 SB-146 3/7/01 1348 01-93 27 1209 18.8659 -64.6077 105 300 38 1 9 SB-147 3/7/01 1504 01-94 27 1692 18.8254 -64.4350 1 9 1 SB-148 3/7/01 1524 01-94/9 27 500 18.7903 -64.2870 120 47 103 1 9 1 SB-149 3/7/01 1600 01-94/9 27 500 18.7650 -64.2617 150 110 160 1 9 SB-150 3/7/01 1659 01-95/9 27 750 18.7445 -64.0570 240 343 302 1 9 SB-151 3/7/01 2107 01-97/9 303 6000 18.7698 -63.6692 45 340 212 1 9, 10 3 SB-152 3/7/01 24 01-98 27 6100 18.7561 -63.7684 0 9 3 SB-153 3/7/01 24 01-99 303 1600 19.0000 -64.0000 1 9 3 SB-155 3/8/01 1059 01-100 27 1600 18.5453 -64.1140 255 213 225 1 9 SB-156 3/8/01 1258 01-101 27 50 18.3346 -64.1939 308 284 315 1 9 1 SB-157 3/8/01 1324 01-101 27 1300 18.3140 -64.2598 45 305 56 1 9 SB-158 3/8/01 1615 01-102 27 2788 18.0195 -64.6330 56 297 31 1 9 SB-159 3/8/01 1705 01-102 2500 17.8936 -64.6632 50 65 265 1 9 SB-160 3/8/01 1915 01-103 27 1100 17.8299 -64.3845 3 55 215 1 9 SB-161 3/8/01 2051 01-103 800 17.6436 -64.5778 1 9, 10, 26 SB-162 3/8/01 2145 01-104 27 800 17.6349 -64.6315 114 134 160 0 9 SB-163 3/11/01 20 01-105 27 6000 19.4704 -67.9657 1 9 1 SB-164 3/11/01 331 01-106 27 3600 19.7522 -68.4936 341 127 50 1 9 3 SB-166 3/11/01 738 01-108 27 4500 20.0559 -69.1917 0 9 SB-167 3/11/01 959 01-109 27 28 20.2262 -69.6034 0 9 SB-169 3/11/01 1452 01-111 27 2000 20.3392 -70.5500 0 9 SB-170 3/11/01 1714 01-111 27 3689 20.4096 -71.0101 1 9 3 SB-171 3/11/01 1741 01-111 27 3700 20.4240 -71.1082 176 61 66 1 2 3 SB-172 3/11/01 1943 01-112 27 3000 20.4871 -71.5172 340 175 193 1 2 1, 3 SB-173 3/12/01 0 01-113 27 4180 20.6122 -72.3159 0 2 SB-174 3/12/01 236 01-114 27 1500 20.6954 -72.8292 0 SB-175 3/13/01 541 none 27 500 20.7800 -72.4120

35 SB-176 3/13/01 1000 01-115 27 2800 21.0000 -74.2230 78 89 1 2 1 TA-01 2/22/01 2354 A01 5000 20.3890 -64.3350 90 150 0 7 1, 2 TA-02 2/23/01 2252 A02 6590 19.5419 -65.4604 0 2(?) TA-03 2/24/01 2340 A03 3000 17.1028 -65.4013 0 TA-04 2/25/01 137 A04 2000 17.5680 -65.2847 0 2 TA-05 2/26/01 1 A05 5000 15.8703 -66.0619 0 2 TA-06 2/27/01 1935 A06 5000 17.0933 -66.4217 0 2 TA-07 2/27/01 2154 A07 5000 17.0552 -66.3380 0 1(?) TA-08 2/28/01 910 A08 5000 17.0000 -66.0000 0 1(?) TA-08B 2/28/01 1733 A08 20 17.8815 -66.6232 90 180 10R 1 4 1 TA-09 2/28/01 1833 A09 1000 17.9173 -66.6701 1 2,4 1 TA-10 2/28/01 2058 A10 2000 17.7472 -66.8750 1 2 2 TA-11 3/1/01 137 A11 2700 17.5911 -67.6332 102 139 167 0 2 2 TA-12 3/2/01 1702 A12 400 18.0888 -67.7670 135 168 29 0 1,2,4,5 TA-13 3/3/01 939 A13 2300 18.0401 -68.0050 0 2 TA-14 3/4/01 1607 A14 150 18.3375 -67.3633 0 2,4 TA-15 3/4/01 1818 A15 75 18.4980 -67.2095 1 2 TA-16 3/5/01 2121 A16 400 18.5523 -66.7545 28 0 2,3 TA-17 3/6/01 1555 A17 2000 18.7277 -66.2570 94/266 128/232 16/344 0 2,4 TA-18 3/6/01 2113 A17 800 18.5545 -65.8313 0 1(?),2,4 TA-19 3/7/01 52 A18 5500 18.7698 -63.6692 105/255 10/350 0 5 TA-20 3/8/01 2050 A18 886 18.7416 -63.8015 271 36/324 0 ? 3

Sound Source / Species Codes:

1 = Ship noise 7 = Balaenoptera edei 17 = Mesoplodon sp. 35 = D. delphus 40 = S. frontalis 2 = Percussive / Explosions 8 = Balaenoptera acutorostrata 23 = Feresa attenuata 36 = T. truncatus 41 = S. coeruleoalba 3 = Light bulb implosions 9 = Megaptera novaeangliae 24 = P. crassidens 37 = G. griseus 42 = S. longirostris 4. = Active Sonar 10 = Physeter macrocephalus 26 = G. macrorhynchus 38 = Stenella sp. 43 = S. clymene 5. = Other 11 = Kogia sp. 29 = Steno bredanensis 39 = S. attenuata 45 = Unid. Dolphin

46 = Unid. Small whale 48 = Ziphius sp. 60 = Bloops 47 = Unid. Large whale 54 = Unid. odontocete

36 37 Table 4. Percussive “explosion-like” sounds detected on sonobuoys and during hydrophone array tows from February 12 to March 8, 2001 around Puerto Rico and the Virgin Islands.

Date Time/UTC DAT / Array Tape Lat (DD) Long (DD) Bearing 1 Bearing 2 Bearing 3 Bearing 4 Bearing 5 Sonobuoy No. SB-95 02/26/2001 1807 01-55 16.0682 65.7905 183 177 180 185 182 SB-96 02/26/2001 2103 01-56 15.6612 65.9961 158 189 SB-99 02/27/2001 1735 01-58 16.8028 66.3195 47 40 43 32 29 SB-100 02/27/2001 2043 01-59 17.1006 66.3807 112 56 65 SB-102 02/28/2001 1331 01-62 17.2771 66.4778 78 80 82 83 86 SB-105 03/01/2001 1125 01-64 17.5575 67.1158 SB-108 03/01/2001 1550 01-66 17.3981 67.4799 75 76 70 66 72 Array Tow No. TA-01 02/22/2001 2354 A-01 20.3891 64.3351 TA-04 02/25/2001 0137 A-04 17.5681 65.2847 TA-05 02/26/2001 0000 A-05 15.8703 66.0619 TA-06 02/27/2001 1935 A-06 17.0933 66.4217 TA-10 02/28/2001 2058 A-10 17.7472 66.8751 TA-11 03/01/2001 0137 A-11 17.5911 67.6332

38 Figure 1. NOAA ship Gordon Gunter.

39 Figure 2. Survey trackline from Abaco Island, Bahamas south to Puerto Rico and the Virgin Islands (solid black line).

78° 76° 74° 72° 70° 68° 66° 64° 26° Abaco 26° Islan d T H E

B A H A N M T o A n g S u e

24° o Sa n W E 24° f th Sa lvador e O c e a S n Saman a Cay Mayaguan a Island

22° 22° Grea t Ina gua TURKS & Mouchoi r Isla nd Bank CAICOS Silver Bank CU BA Navi dad Bank 20° 20°

Virg in Isla nds HAITI Samana Bay DOMINICAN Anegada Enga no Isl and REPUBLIC Ban k

PU ERTO RIC O Isla Ca bo Vi eques Is land Mono Saon a Ro jo Island 18° St. Croi x 18° Saba

16° 16°

78° 76° 74° 72° 70° 68° 66° 64°

40 Figure 3. Marine mammal observers at the “big-eye” 25x binoculars.

41 Figure 4. Illustration of a typical DIFAR sonobuoy utilized in the survey.

42 Figure 5. A 3-D plot showing signal intensity as a function of frequency and bearing angle from 00 to 3600, showing a single calling whale at a bearing of 1010 magnetic from the sonobuoy’s location and major acoustic energy between 450 Hz to 650 Hz.

43 Figure 6. Illustrations of the towed 5-element hydrophone array and signal monitoring and trackin g laboratory utilized in the survey.

44 45 Figure 7. An autonomous bottom acoustic recording device or “pop-up” buoy developed by C. Clark of Cornell University and deployment operations for one device placed in the Mona Channel.

46 47 Figure 8. An example of the recordings from one autonomous bottom acoustic recording device or “pop-up” buoy developed by C. Clark of Cornell University. The spectrogram shows sound energy (spectrum level) versus time of day (GMT) recorded on February 19, 2001 in Mono Channel. The sound energy peaks represent close approaches by passing vessels. Marine mammal sounds, mostly humpback whale calls are also embedded in these data.

48 Figure 9. Sightings of humpback whales (triangles, n=72) during visual surveys (black line) along the eastern and southern sides of the Bahamas south to Puerto Rico and the Virgin Islands.

73° 71° 69° 67° 65° 63°

23° 23° Samana Cay N Mayaguana Island W E

S

G re at Mouc hoir Inagua TURKS & Bank Island Si lver 21° CAICOS $T$T 21° T$T$$TT$ Bank $TT$T$$TT$$ T$T$TT$ T$$ T$T $T T$T$T$ TT$ $T Nav i dad $T Bank

T$

Vir gin Islands HAITI Samana Bay 19° DOMINICAN En gano Anega da 19° $T T$ $T Is$land $ B ank $T $T T$ T T REPUBLIC T$ $ T$ T$ $TT$T$$T $T$TT $T $TT$ T$ $ $T T T$ PUERT O RICO T$ $T $ $T Isla T$$T Cabo Vi equ es Isla nd $T Saona Mono Rojo $$ Is land TTT$ $TS t. Croix

Saba B ank

17° 17°

73° 71° 69° 67° 65° 63°

49 Figure 10. Sightings of dolphins during visual surveys (black lines): Steno bredanensis (star, n=1), Tursiops truncatus (triangle, n = 2), Stenella attenuata (circles, n = 3), Stenella frontalis (squares, n = 10), and Stenella longirostris (diamonds, n = 2).

69° 68 ° 67° 66 ° 65° 6 4°

Navidad Bank N 20° 20 ° W E

S

Virgin Islands Samana Bay ÚÊ #

19° $T Anegada 19 ° Engano Island Bank %U &V

PUERTO RICO %U Cabo Vieques Island 18° Isla &V 18 ° Mono Rojo Saona # %U %U $T Island %U St. Croix # %U %U %U Saba Bank

17° 17 °

%U

%U

16° 16 °

69° 68 ° 67° 66 ° 65° 6 4°

50 51 Figure 11. Sightings of odontocete whales during visual surveys (black lines): Physeter macrocephalus (circles, n = 5), Ziphius spp. (triangles, n = 3), Mesoplodon spp.(squares, n = 3), Pseudorca crassidens (star, n = 1), and Globicephala spp. (diamonds, n = 8).

68° 66° 64° 62°

21° 21° N

W E #S Navidad Ban k S &V

Samana Bay $T &V 19° #S 19° $T Anegada Engan o &V Island Bank &V Virgin Islands

&V %U PUERTO RICO Ang ui lla St. Ma rtin #S Vieques Isla nd Isla Mo no St. Ba rth Saona #S Isla nd Ca bo %URo jo $T &V St. Croi x ÚÊ &V St. Kits Saba Bank Nevi s

#S 17° 17°

%U

68° 66° 64° 62°

52 Figure 12. Survey track line along the eastern side 76° 74° 72° 70° 68° 66° 64° of the Bahamas, around T H Puerto Rico E and the Virgin Islands (black # B A line) # H showing location of A # M San N sonobuoy o A drops (circles) and f S 24°th Salvador 24° e O c hydrophone e W E array tows (bold lines). a n

Samana # C ay # S #

# Mayaguana

# Island

# #

22° # 22°

# Great Mouch oir Inagua TURKS & Island #Ban k CAICOS # Si lver # # Ban k # # # # # # # # # # # # # # C # U # BA # Navidad # # Bank 20° # # 20° # # # # # # # # # Virgi n Isla nds Samana Bay # HAITI # # # DOMINICAN # # # # # Anegada Enga no # # # # # # Island # # # # ## # # # REPUBLIC Ba nk # # # # # # # # # # # # # # PU PU U # # PUERTO RICO ## # # Ca bo # Vi eques I sland # # PU # # # # Ro jo # Isla # Mono # 18° # # ## # 18° Saona Island # # # # # # ## St . Croix # # # # # # # Saba Ba # # # # # # # # # #

#

# # # 16° 16° #

76° 74° 72° 70° 68° 66° 64°

53 75° 73° 71° 69°

T H E

B # A H A # M N Figure 13. Survey A trackline along the # S eastern side of the W E Bahamas, the Turks 24° S 24° and Caicos, San Mouchoir, Silver, and Navidad Banks Salvador (black line) showing Samana # location of sonobuoy # Cay drops with magnetic bearings to calling # humpback whales # Mayaguana

(circles with radials). # Island

# # TURKS & 22° # CAICOS 22° Great # Inagua Mouchoir Bank Island # Silver # # Bank

# # # # # Navidad # # # Bank CU # BA # # 20° # 20° # #

# # Samana Bay # HAITI # DOMINICAN Engano 75° 73° R7E1° PUBLIC 69°

54 55 Figure 14. Acoustic detections of humpback whales during surveys to the north of Puerto Rico and the Virgin Islands showing the location of sonobuoy drops and magnetic bearings to singing humpback whales (circles with radials).

67° 66° 65° 64° 63°

21° #Y 21° #Y #Y N #Y #Y W E

#Y S #Y #Y

#Y 20° 20° #Y

#Y

#Y

#Y Virgin Islands #Y #Y #Y #Y #Y 19° #Y #Y #Y Anegada 19° #Y #Y Island #Y #Y #Y #Y #Y #Y #Y #Y #Y #Y #Y Anguilla #Y #Y #Y St. Martin #Y #Y St. Barth #Y #Y

PUERTO RICO #Y #Y #Y Vieques Island 18° #Y #Y 18° #Y bo #Y 67° 66° 65° 64° 63°

56 Figure 15. Acoustic detections of humpback whales during surveys to the south of Puerto Rico and the Virgin islands showing the location of sonobuoy drops with magnetic bearings to singing humpback whales (circles with radials). Location of one autonomous acoustic recording device is indicated by a i.

67° 66° 65° 64° #

# # #

# PUERTO RICO # Anguilla # St. Martin 18° Ê Vieques Island # 18° Ú # St. Barth # # # # # #

# # # # # # St. Croix # # # # Saba Bank # # #

# #

# # 17° # 17°

#

# N

W E

# S # #

16° 16°

#

67° 66° 65° 64°

57 Figure 16. Acoustic detections of humpback whales during surveys to the west and southwest of Puerto Rico showing the location of sonobuoy drops and magentic bearings to singing humpback whales (circles with radials).

69°00' 68°30' 68°00' 67°30' 67°00' 66°30' # # # #

#

# Engano # # # DOMINICAN Bank REPUBLIC Borinquen # Bank 18°30' Desecheo 18°30' # # Island # # Rincon # # PUERTO RICO # #

# # Isla # 18°00' 18°00' Saona # # Mona # Island Cabo # # Rojo

#

# N #

# W E 17°30' # 17°30'

S # # #

#

17°00' 17°00' 69°00' 68°30' 68°00' 67°30' 67°00' 66°30'

58 Figure 17. Acoustic detections of humpback whales during surveys to west and northwest of Puerto Rico showing the location of sonobuoy drops and magnetic bearings to singing humpback whales (circles with radials). The location on one autonomous acoustic recording device is noted by a i.

69°00' 68° 30' 68°00' 67° 30' 67°00' 66°30'

Navidad Bank

20° 00' 20° 00'

# N

#

# W E

S

19° 30' 19° 30' #

#

Samana Bay

# # # 19° 00' # # 19° 00'

#

# Engano # DOMINICAN # # Bank Borinquen REPUBLIC # Bank Desecheo # 18° 30' 18° 30' # Island # # Rincon PUERTO RICO

# # # #

# 69°00' 68° 30' 68°00' 67° 30' 67°00' 66°30'

59 Figure 18. Location of acoustic detections of sperm whales (n=12) made by sonobuoys and during hydrophone array tows around Puerto Rico and the Virgin Islands from February 12 to 8 march, 2001.

68° 67° 66° 65° 64° 63°

21° 21° #Y

#Y

N 20° Navidad 20° Bank W E

S

a Bay #Y 19° #Y 19° Anegada Engano #Y OMINICAN Bank Island EP UBLIC Virgin Islands

PUERTO RICO Anguilla Isla Vieques Island St. Martin 18° Saon a #Y Mono #Y St. Barth 18° #Y Islan d Cab o Rojo #Y #Y St. Croix

Saba Bank #Y #Y

17° 17°

68° 67° 66° 65° 64° 63°

60 Figure 19. Location of 79 of the 135 sonobuoys (circles) that detected Atlantic “thumptrains” throughout the study area between February 12 and March 8, 2001.

76° 74° 72° 70° 68° 66° 64°

B A H #Y A M A #Y S

#Y San Sal vad or 24° 24° N Saman a #Y#Y Cay #Y W E #Y Mayag uan a #Y Island #Y S #Y 22° 22° #Y G rea t Mouch oi r In ag ua TURKS & Bank Is land CAICOS #Y #Y #Y #Y #Y Si lver #Y #Y #Y Bank #Y #Y CUBA Navi dad #Y Bank #Y 20° #Y 20° #Y#Y HAITI #Y #Y Sam ana B ay #Y DO MIN ICAN #Y #Y #Y #Y #Y REPUBLIC #Y #Y #Y An eg ad a Engano #Y #Y#Y#Y #Y #Y Bank #Y #Y Is lan d #Y #Y Vi rg in Islands #Y #Y#Y #Y #Y #Y #Y PUERT O RICO #Y Anguilla #Y Vi equ es Isla nd St. Martin 18° Isla Mono #Y #Y St. Bar th 18° Sao na Island #YC ab o #Y #Y R ojo #Y #Y #Y #Y St . Croix #Y #Y #Y#Y #Y #Y #Y #Y Sa ba Ban k #Y #Y #Y

#Y 16° #Y 16° #Y

76° 74° 72° 70° 68° 66° 64°

61 Figure 20. Spectrogram of a typical Atlantic “thumptrain” recorded during the February-March marine mammal survey around Puerto Rico and the Virgin Islands. The thumptrain consists of a 1-2 minute series of discrete repetitive pulses that increase in intensity and frequency, and terminate abruptly. Major sound energy is centered between 100 Hz and 650 Hz.

62 Figure 21. Locations where percussive “explosion-like” sounds were detected by sonobuoys and during towed hydrophone array sampling (circles). Radials from circles indicate magnetic bearings to the sources of the sounds.

69° 68° 67° 66° 65° 64° # # #

# #

#

# #

# # Virgin Islands # Samana Bay # # 19° # # 19° # # # # # Anegada # # # Engano # # # # Island # # # # # Bank ## # # # # # # # # # # # # #

# # # # PUERTO RICO # # # # # Vieques Island # Cabo # 18° # # # 18° # # Isla Mono Rojo # # # # # # # Saona Island # # # # # # # St. Croix # # # # # # # # # Saba Bank # # #

# #

# # 17° # 17° N #

W E #

S

# # #

16° 16°

#

69° 68° 67° 66° 65° 64°

63 64 Figure 22. A spectrogram of a percussive “explosion-like” sound recorded off the south coast of Puerto Rico on February 27, 2001. Sound energy between 100 Hz and 20 kHz (upper line) averaged approximately 26.86 dB above the ambient noise level (lower line) in the area just prior to the occurrence of the percussive sound.

65 Figure 23. The locations along the survey track line (thin line) where commercial ship noise was detected (circles) by sonobuoys and during towed hydrophone array sampling (bold lines) from February 12 to march 8, 2001.

73° 71° 69° 67° 65° Sa lva dor

Sam ana Cay 23° 23°

Mayaguana N Island

#Y W E #Y S Great TURKS & Mouchoi r Inagu a Bank Island CAICOS 21° #Y 21°

Silv er #Y Bank #Y Navida d Ba nk

HAITI #Y #Y Sama na Bay #Y #Y #Y #Y 19° DOMINICAN #Y #Y 19° Ane ga da REPUBLIC Eng ano #Y#Y Ba nk Island V#Yirgin Islan#Yds #Y PUERTO RICO Vie que s Island Isla #Y Mo no #Y Isl and Cabo #Y Saona Rojo #Y #Y #Y St. Croix #Y #Y Sa

17° 17°

73° 71° 69° 67° 65°

66 Figure 24. A proposed survey track line around Puerto Rico for future acoustic and visual surveys based on the marine mammal sighting rates obtained during the February-March 2001 survey.

68° 67° 66° 65° 64° 63°

Navidad Bank N 20° 20°

W E

S

Bay

19° 19°

Anega da Enga no Virgin Islands Ba nk Island

PUERTO RICO Barracud a Bank I sla Saona Cabo 18° Mono Rojo Vieque s I sland 18° I sland

St. Croix

Sa ba Bank

17° 17°

68° 67° 66° 65° 64° 63°

67